JPH11236615A - Manufacturing method of high chromium cast iron casting for impact wear resistance - Google Patents
Manufacturing method of high chromium cast iron casting for impact wear resistanceInfo
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- JPH11236615A JPH11236615A JP5621398A JP5621398A JPH11236615A JP H11236615 A JPH11236615 A JP H11236615A JP 5621398 A JP5621398 A JP 5621398A JP 5621398 A JP5621398 A JP 5621398A JP H11236615 A JPH11236615 A JP H11236615A
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- cast iron
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Abstract
(57)【要約】
【課題】 硬さを犠牲にすることなく、かつ熱処理に長
時間を必要とすることなく残留応力を最小にし得る耐衝
撃摩耗高クロム鋳鉄鋳物の製造方法を提供する。
【解決手段】 Ｃ ２．０〜３．５ｗｔ％、Ｓｉ ０．
５〜１．５ｗｔ％、Ｍｎ０．５〜２．５ｗｔ％、Ｃｒ
２０〜３５ｗｔ％及び残部がＦｅと不可避不純物からな
り、硬さがＨＲＣ５８以上の耐衝撃摩耗用高クロム鋳鉄
鋳物の製造に際し、鋳造物を加熱炉中で９００〜１１０
０℃の温度で均一加熱し、常温まで約１００℃／ｍｉｎ
の冷却速度で衝風冷却した後、４００〜５５０℃の温度
で焼戻す。
PROBLEM TO BE SOLVED: To provide a method for producing an impact-resistant high-chromium cast iron casting capable of minimizing residual stress without sacrificing hardness and without requiring a long time for heat treatment. SOLUTION: C 2.0 to 3.5 wt%, Si 0.
5 to 1.5 wt%, Mn 0.5 to 2.5 wt%, Cr
When producing a high chromium cast iron casting for impact wear having a hardness of HRC 58 or more, the casting is 900-110 wt% in a heating furnace.
Uniform heating at a temperature of 0 ° C, and about 100 ° C / min to room temperature
And then tempered at a temperature of 400 to 550 ° C.
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、破砕機や粉砕機等
の耐摩耗部品である打撃板、衝突板、ライナ等の耐衝撃
摩耗用高クロム鋳鉄鋳物の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high chromium cast iron product for impact wear such as impact plates, impact plates, liners, etc., which are wear components such as crushers and crushers.
【０００２】[0002]
【従来の技術】通常、耐衝撃摩耗用高クロム鋳鉄鋳物
は、Ｃ ２．０〜３．５ｗｔ％、Ｓｉ０．５〜１．５ｗ
ｔ％、Ｍｎ ０．５〜１．５ｗｔ％、Ｃｒ ２０〜３５
ｗｔ％及び残部がＦｅと不可避不純物からなり、硬さが
ＨＲＣ（ロックウエル硬さのＣスケール）５８以上のも
のが用いられている。従来、耐衝撃摩耗用高クロム鋳鉄
鋳物は、重量１００ｋｇ以下の小物製品に限り鋳放しの
まま使用されることがあるが、この方法では、型ばらし
時の冷却が不均一になると組織的なばらつきを生じるた
め、鋳造後にオーステナイト化温度（９００〜１１００
℃）に１〜２時間保持する不安定化熱処理を行った後、
約５０〜１５０℃／ｍｉｎ（約９００〜５００℃の間）
の冷却速度で衝風冷却し、基地組織を硬いマルテンサイ
トを主体としたものとする空気焼入れ処理（TE.Norman,
K.Rohring：Autbereitungs-Technik(1970)6 356、 W.Fa
irhurst, K.Roring：Foundry Trade Journal 136(1974)
685 、 R.S.Jackson：British Foundrymen 67(1974)34
、 G.J.Cor：Foundry Trade Journal 158(1985)480参
照）したり、空気焼入れ処理後に２００〜３５０℃程度
の温度での低温焼戻し処理したり、又は６００℃以上の
温度での高温焼戻し処理したりして製造されている（先
行技術文献として、特開昭５６−４７５４５号公報、特
開昭６０−２１３２３号公報、特開昭６２−１８５８２
５号公報、特開昭５７−８９４５３号公報、特開昭５９
−１２９７２０号公報等がある。）。2. Description of the Related Art Usually, a high chromium cast iron casting for impact wear resistance is composed of 2.0 to 3.5 wt% of C and 0.5 to 1.5 watts of Si.
t%, Mn 0.5-1.5 wt%, Cr 20-35
A material having a wt% and balance of Fe and unavoidable impurities and having a hardness of HRC (C scale of Rockwell hardness) of 58 or more is used. Conventionally, high-chromium cast iron castings for impact wear are often used as-cast only for small products weighing 100 kg or less. However, this method requires systematic dispersion when the cooling during unmolding becomes uneven. Austenitic temperature (900 to 1100) after casting.
C) for 1-2 hours.
About 50-150 ° C / min (between about 900-500 ° C)
Air quenching treatment to cool the base structure with hard martensite as the main component (TE. Norman,
K. Rohring: Autbereitungs-Technik (1970) 6 356, W. Fa
irhurst, K. Roring: Foundry Trade Journal 136 (1974)
685, RSJackson: British Foundrymen 67 (1974) 34
GJCor: Foundry Trade Journal 158 (1985) 480), after air quenching, low-temperature tempering at a temperature of about 200 to 350 ° C, or high-temperature tempering at a temperature of 600 ° C or more. It is manufactured (as prior art documents, JP-A-56-47545, JP-A-60-21323, JP-A-62-15852).
No. 5, JP-A-57-89453, JP-A-57-89453
No. 129720. ).
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
空気焼入れ処理による耐衝撃摩耗高クロム鋳鉄鋳物の製
造方法では、オーステナイトを多く残留させた場合、鋳
物の形状や大きさによっては、製造時や使用時に鋳物が
変形したり割れる不具合がある。一方、上記空気焼入れ
処理後に焼戻しを行う場合には、残留応力が軽減され、
かつ、耐摩耗性が調整されて上述した不具合は解消され
るが、高温焼戻し処理を施す場合、硬さが低下し、耐用
寿命が短くなり、又、低温焼戻し処理を行う場合、耐用
寿命が長くなるものの、処理に長時間を要し、それでも
十分に残留応力を下げることができない不具合がある。
そこで、本発明は、硬さを犠牲にすることなく、かつ熱
処理に長時間を必要とすることなく残留応力を最小にし
得る耐衝撃摩耗高クロム鋳鉄鋳物の製造方法を提供する
ことを目的とする。However, according to the conventional method for producing a high-abrasion-resistant high-chromium cast iron casting by air quenching, when a large amount of austenite remains, depending on the shape and size of the casting, the production and use of the casting may be difficult. There is a problem that the casting is sometimes deformed or cracked. On the other hand, when tempering is performed after the air quenching treatment, the residual stress is reduced,
In addition, although the above-mentioned problem is solved by adjusting the wear resistance, when performing high-temperature tempering, the hardness is reduced, the service life is shortened, and when performing low-temperature tempering, the service life is increased. However, there is a problem that the treatment requires a long time, and the residual stress cannot be sufficiently reduced.
Therefore, an object of the present invention is to provide a method for producing an impact-resistant high chromium cast iron casting that can minimize residual stress without sacrificing hardness and without requiring a long time for heat treatment. .
【０００４】[0004]
【課題を解決するための手段】前記課題を解決するた
め、本発明の耐衝撃摩耗高クロム鋳鉄鋳物の製造方法
は、Ｃ ２．０〜３．５ｗｔ％、Ｓｉ ０．５〜１．５
ｗｔ％、Ｍｎ ０．５〜２．５ｗｔ％、Ｃｒ ２０〜３
５ｗｔ％及び残部がＦｅと不可避不純物からなり、硬さ
がＨＲＣ５８以上の耐衝撃摩耗用高クロム鋳鉄鋳物の製
造に際し、鋳造物を加熱炉中で９５０〜１１００℃の温
度で均一加熱し、常温まで約１００℃／ｍｉｎの冷却速
度で衝風冷却した後、４００〜５５０℃の温度で焼戻す
ことを特徴とする。前記焼戻しの加熱保持時間は、５〜
１５時間とすることが好ましい。又、前記耐衝撃摩耗用
高クロム鋳鉄鋳物は、１ｗｔ％以下のＮｉ，Ｍｏ及びＶ
をそれぞれ含有していることが好ましい。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method for producing an impact-resistant and high-chromium cast iron casting according to the present invention comprises: 2.0 to 3.5 wt% of C and 0.5 to 1.5% of Si.
wt%, Mn 0.5-2.5wt%, Cr 20-3
5% by weight and the balance of Fe and inevitable impurities, the hardness of which is HRC58 or more, when manufacturing a high chromium cast iron casting for impact resistance, the casting is uniformly heated in a heating furnace at a temperature of 950 to 1100 ° C. After blast cooling at a cooling rate of about 100 ° C./min, tempering is performed at a temperature of 400 to 550 ° C. The heat holding time of the tempering is 5 to 5.
Preferably, it is 15 hours. In addition, the high chromium cast iron casting for impact wear resistance contains Ni, Mo and V of 1 wt% or less.
Respectively.
【０００５】加熱炉中での鋳造物の加熱温度が９５０℃
未満であると、空気焼入れ処理後の硬さが低くなり、１
１００℃を超えると、残留オーステナイトが多くなり、
やはり硬さが低下する。好ましい加熱温度は、９５０〜
１０５０℃である。冷却速度が約１００℃／ｍｉｎから
外れると、焼割れが生じたり、逆に焼入れ不良となる。
焼戻し温度が４００℃未満であると、残留応力が短時間
のうちに十分低減されず、鋳物の製造時や使用中に割れ
を生じることがある。一方、５５０℃を超えると、硬さ
が低下し耐用寿命も短くなる。好ましい焼戻し温度は、
４００〜４５０℃である。焼戻しの加熱保持時間が５時
間未満であると、十分な焼戻し硬化が得られず、１５時
間を超えると、硬さが低下してくるため、耐用寿命が短
くなる。好ましい加熱保持時間は、８〜１２時間であ
る。耐衝撃摩耗用高クロム鋳鉄鋳物がＮｉ，Ｍｏ及びＶ
を含有すると、焼入れ性や耐用寿命が改善される。しか
し、それぞれの含有量が１ｗｔ％を超えると、焼入れ性
が必要以上に上がり、割れが生じることがあると共に、
材料のコストを上げる。好ましいそれぞれの含有量は、
０．５〜１．０ｗｔ％である。一方、耐衝撃摩耗用高ク
ロム鋳鉄鋳物のＣｒの含有量は、２０〜３５ｗｔ％が好
ましかった。The heating temperature of the casting in the heating furnace is 950 ° C.
If it is less than 1, the hardness after the air quenching becomes low,
When the temperature exceeds 100 ° C., retained austenite increases,
After all hardness decreases. The preferred heating temperature is 950 to
1050 ° C. If the cooling rate deviates from about 100 ° C./min, quenching cracks occur, and conversely, quenching failure occurs.
If the tempering temperature is lower than 400 ° C., the residual stress is not sufficiently reduced in a short time, and cracks may occur during the production or use of the casting. On the other hand, if it exceeds 550 ° C., the hardness is reduced and the service life is shortened. The preferred tempering temperature is
400-450 ° C. If the heating holding time of the tempering is less than 5 hours, sufficient tempering hardening cannot be obtained, and if it exceeds 15 hours, the hardness decreases, and the service life is shortened. A preferred heating holding time is 8 to 12 hours. High chromium cast iron casting for impact wear resistance is Ni, Mo and V
, Hardenability and service life are improved. However, if the content of each exceeds 1 wt%, the hardenability increases more than necessary, and cracks may occur,
Increase material costs. The preferred content of each is
It is 0.5 to 1.0 wt%. On the other hand, the content of Cr in the high chromium cast iron casting for impact resistance was preferably 20 to 35 wt%.
【０００６】[0006]
【発明の実施の形態】以下、本発明の実施の形態につい
て具体的な実施例１，２及び比較例１〜５を参照して説
明する。 実施例１，２、比較例１〜５ 先ず、共晶成分に近い３ｗｔ％Ｃ−２５ｗｔ％Ｃｒ系の
高クロム鋳鉄を得るため、銑鉄、ＳＳ棒鋼、フェロクロ
ム、フェロマンガン及びフェロシリコンを所要量ずつ高
周波誘導炉を用いて溶解し、溶け落ち後溶湯を約１３９
７℃（１６７０Ｋ）の温度に昇温して取鍋内にて１２９
７℃（１５７０Ｋ）になった時点で、ＪＩＳ Ｇ ０３
０７供試材（ａ）に規定されている鋳込み重量約２０ｋ
ｇを各テストピース用鋳型に鋳込んだ。冷却後、押湯を
切除した各供試材を大気雰囲気の加熱炉中において１０
５０℃（１３２３Ｋ）の温度で２時間保持して均一加熱
処理した。熱処理後の冷却方法は衝風冷却であり、半冷
温度と半冷時間から求めた平均冷却速度は、約１００℃
／ｍｉｎであった。次いで、熱処理後の各供試材を未処
理、加熱炉中において２００〜７００℃（４７３〜９７
３Ｋ）の範囲で１００℃の温度間隔で１０時間保持した
後、炉外で自然放冷する焼戻しを行って実施例１，２
（焼戻し温度４００℃，５００℃）、比較例１（未処
理）、比較例２〜５（焼戻し温度２００℃，３００℃，
６００℃，７００℃）の供試材を得た。各供試材の化学
成分と熱処理条件を表１に示す。DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to specific Examples 1 and 2 and Comparative Examples 1 to 5. Examples 1 and 2 and Comparative Examples 1 to 5 First, pig iron, SS bar, ferrochrome, ferromanganese and ferrosilicon were added in required amounts in order to obtain a 3 wt% C-25 wt% Cr-based high chromium cast iron close to the eutectic component. Melt using a high-frequency induction furnace.
The temperature was raised to a temperature of 7 ° C (1670K) and 129 was set in the ladle.
When the temperature reaches 7 ° C. (1570K), JIS G 03
07 Casting weight specified in test material (a) about 20k
g was cast into each test piece mold. After cooling, each specimen from which the feeder was cut was placed in a heating furnace in an air atmosphere for 10 minutes.
It was kept at a temperature of 50 ° C. (1323 K) for 2 hours to perform a uniform heat treatment. The cooling method after the heat treatment is blast cooling, and the average cooling rate obtained from the half-cooling temperature and half-cooling time is about 100 ° C.
/ Min. Next, each of the test materials after the heat treatment was untreated, and was heated at 200 to 700 ° C. (473 to 97 ° C.) in a heating furnace.
After holding for 10 hours at a temperature interval of 100 ° C. within the range of 3K), tempering was performed by allowing the material to cool naturally outside the furnace.
(Tempering temperatures 400 ° C, 500 ° C), Comparative Example 1 (untreated), Comparative Examples 2 to 5 (tempering temperatures 200 ° C, 300 ° C,
(600 ° C., 700 ° C.). Table 1 shows the chemical components and heat treatment conditions of each test material.
【０００７】[0007]
【表１】 [Table 1]
【０００８】次に、各供試材から所定のテストピースを
切断採取し、マクロ硬さの測定、引張試験、衝撃試験、
衝撃摩耗試験及び残留応力の測定を行った。マクロ硬さ
の測定は、ロックウエル硬度計のＣスケールにて各テス
トピースの切断面を約２０点計測し、その平均値を求め
たところ、図１に示すようになった。図１から、均一加
熱処理後の硬さは、ＨＲＣ６５程度であるが、焼戻し温
度が、高くなるにつれて硬さがわずかに下がり、３９７
℃（６７０Ｋ）近辺でわずかに二次硬化した後、基地中
の残留オーステナイトの分解が顕著になるため急激に下
がり、６９７℃（９７０Ｋ）を超えるとＨＲＣ４０程度
になっていることがわかる。Next, a predetermined test piece is cut and sampled from each test material, and a macro hardness measurement, a tensile test, an impact test,
An impact wear test and measurement of residual stress were performed. The measurement of the macro hardness was performed by measuring about 20 points on the cut surface of each test piece on a C scale of a Rockwell hardness tester, and the average value was obtained. The result was as shown in FIG. From FIG. 1, the hardness after the uniform heat treatment is about HRC65, but the hardness decreases slightly as the tempering temperature increases,
It can be seen that, after a slight secondary hardening near ℃ (670K), the decomposition of the retained austenite in the matrix becomes remarkable, so that the temperature drops sharply, and when it exceeds 697 ° C (970K), the HRC becomes about 40.
【０００９】引張試験は、５ｍｍの径で平行部長さ２５
ｍｍの各テストピースを用い、０．５ｍｍ／ｍｉｎの定
速ひずみで行ない、破断時の引張強度を調べたところ、
図２に示すようになった。図２から、引張強度は、７０
０〜９００ＭＰａであるが、焼戻し温度との相関がない
ことがわかる。[0009] The tensile test was conducted with a diameter of 5 mm and a parallel part length of 25.
Using each test piece of 0.5 mm / min at a constant speed of 0.5 mm / min, and examining the tensile strength at break,
As shown in FIG. From FIG. 2, the tensile strength is 70
Although it is 0 to 900 MPa, it is understood that there is no correlation with the tempering temperature.
【００１０】衝撃試験は、１０×１０×５５ｍｍのノッ
チなし形状の各テストピースで、荷重５ｋｇのシャルピ
ー試験機を用い、破断時の吸収エネルギーを調べたとこ
ろ、図３に示すようになった。図３から、焼戻し温度
が、５００℃（７７３Ｋ）でわずかに吸収エネルギーが
下がり、６００℃（８７３Ｋ）で再び上昇しているが、
いずれの温度でもその値は低く２〜３Ｊで、焼戻し温度
と靱性に大きな相関がないことがわかる。[0010] In the impact test, the absorbed energy at the time of breaking was measured using a Charpy tester with a load of 5 kg on each test piece having a notch shape of 10 x 10 x 55 mm, and the results are as shown in Fig. 3. From FIG. 3, the tempering temperature slightly decreased at 500 ° C. (773 K) and increased again at 600 ° C. (873 K).
At any temperature, the value was as low as 2 to 3 J, indicating that there is no great correlation between the tempering temperature and the toughness.
【００１１】衝撃摩耗試験は、インペラーブレーカ型の
試験機を用い、約３００ｋｇの石を破砕し、破砕前後の
各テストピース（打撃板）の重量より摩耗減量を測定し
たところ、図４に示すようになった。図４から、焼戻し
温度が高くなるにつれて摩耗量が増加し、特に５００℃
（７７３Ｋ）を超えると急激に摩耗量が増えていること
がわかる。なお、試験に用いた石は、ＳｉＯ2 を約７８
ｗｔ％含有した硅石で、粒径が５〜２０ｍｍである。
又、打撃板の周速は２９ｍ／ｓ、打撃板と衝突板との間
隔は１５ｍｍである。In the impact wear test, an impeller breaker type testing machine was used to crush about 300 kg of stone, and the wear loss was measured from the weight of each test piece (strike plate) before and after crushing, as shown in FIG. Became. From FIG. 4, it can be seen that the wear amount increases as the tempering temperature increases,
(773K), it can be seen that the abrasion amount rapidly increases. The stone used in the test was SiO 2 of about 78
It is silica stone containing wt%, and the particle size is 5 to 20 mm.
The peripheral speed of the striking plate is 29 m / s, and the distance between the striking plate and the collision plate is 15 mm.
【００１２】残留応力の測定は、図５に示すように、直
径３０ｍｍの球状の鋳物(casting ball)の表面４ケ所に
ひずみゲージ(strain gauge)を貼り付け、熱がかからな
いように注意しながらワイヤーソーを用いて切断し、最
後に約１０×１０×２ｔｍｍの小片になった時のひずみ
量をデジタル静ひずみ計によって行ったところ、図６に
示すようになった。図６から、鋳込み直後に型ばらしし
て急冷したもの(Shake out immediately and rapid coo
ling in air)と、砂型中で徐冷後に型ばらししたもの(S
low cooling in the sand mold) のいずれも４２７〜４
７７℃（７００〜７５０Ｋ）の焼戻し温度で、残留応力
が最小値を示していることがわかる。なお、ひずみゲー
ジは、ゲージ長１ｍｍ、ゲージ抵抗１２０Ω、ゲージ率
２．０６（東京測器研究所 ＦＲＡ−１−１１−１
Ｌ）、接着剤は、シアノアクリレート系（同社のＣ
Ｎ）、コーティング剤は、アラルダイトラピッド（昭和
高分子）を用いた。As shown in FIG. 5, the measurement of the residual stress is performed by attaching strain gauges to four surfaces of a spherical casting (casting ball) having a diameter of 30 mm and paying attention to the heat while avoiding heat. Cutting was performed using a saw, and finally, when a small piece of about 10 × 10 × 2 tmm was obtained, the amount of strain was measured by a digital static strain meter, and the result was as shown in FIG. FIG. 6 shows that the mold was separated immediately after casting and was rapidly cooled (Shake out immediately and rapid coo
ling in air)
low cooling in the sand mold)
It can be seen that at a tempering temperature of 77 ° C. (700 to 750 K), the residual stress shows a minimum value. In addition, the strain gauge has a gauge length of 1 mm, a gauge resistance of 120Ω, and a gauge factor of 2.06 (FRA-1-11-1, Tokyo Sokki Laboratory).
L), adhesives are cyanoacrylate-based (C
N), Araldiprapid (Showa Kobunshi) was used as the coating agent.
【００１３】一方、マクロ硬さと衝撃摩耗量との関係を
調べるため、前述したインペラーブレーカ型の試験機を
用い、マクロ硬さの異なる各テストピースの衝撃摩耗量
を同様に測定したところ、従前のデータをも含めた図７
に示すようになった。図７において□は鋳放しのまま、
○は空気焼入れ処理、△は焼戻し処理のテストピースを
示し、又、実線はオーステナイトが０〜６０ｗｔ％、破
線はオーステナイトが７０〜９０ｗｔ％のテストピース
を示す。図７から、マクロ硬さと衝撃摩耗量には相関が
あり、マクロ硬さが高くなるにつれて衝撃摩耗量が低下
することがわかる。On the other hand, in order to examine the relationship between the macro hardness and the impact wear amount, the impact wear amount of each test piece having a different macro hardness was measured in the same manner using the impeller breaker type testing machine described above. Fig. 7 including data
It became as shown in. In FIG. 7, □ is as cast,
○ indicates a test piece of the air quenching treatment, and △ indicates a test piece of the tempering treatment, and the solid line indicates a test piece of 0 to 60 wt% of austenite, and the broken line indicates a test piece of 70 to 90 wt% of austenite. FIG. 7 shows that there is a correlation between the macro hardness and the impact wear amount, and the impact wear amount decreases as the macro hardness increases.
【００１４】上述したことから次のことが言える。 １）マクロ硬さは、焼戻し温度を上げるにつれて低下
し、焼戻し温度が４２７℃（７００Ｋ）を超えると、急
激に下がる。しかし、引張強度及び靱性は大きな変化が
無く、焼戻し温度の影響をほとんど受けない。 ２）衝撃摩耗量と焼戻し温度には相関があり、焼戻し温
度を上げるにつれてわずかに増加し、焼戻し温度が４２
７℃（７００Ｋ）を超えると急激に増加する。 ３）残留応力は、焼戻し温度を上げるにつれて減少する
が、焼戻し温度が４２７〜４７７℃（７００〜７５０
Ｋ）で最小値をとり、それ以後増加する。これは、焼戻
し温度の上昇と共に応力緩和が進むのと、４２７℃（７
００Ｋ）以上で生じる残留オーステナイトの分解及び焼
戻し後の冷却中に生じる熱応力により、新たに発生する
応力が温度と共に増加するためと考えられる。 ４）加熱炉中で９５０〜１１００℃の温度で１〜２時間
保持して均一加熱処理してから衝風冷却した後に優れた
耐摩耗性を保ったまま残留応力を最小にするには、焼戻
し温度を約４２７℃（７００Ｋ）にするのが適当であ
る。The following can be said from the above. 1) The macro hardness decreases as the tempering temperature increases, and sharply decreases when the tempering temperature exceeds 427 ° C (700K). However, the tensile strength and toughness do not change significantly and are hardly affected by the tempering temperature. 2) There is a correlation between the amount of impact wear and the tempering temperature, which increases slightly as the tempering temperature increases,
When the temperature exceeds 7 ° C. (700 K), it rapidly increases. 3) The residual stress decreases as the tempering temperature increases, but when the tempering temperature is 427 to 477 ° C (700 to 750 ° C).
K) takes the minimum value and increases thereafter. This is because stress relaxation progresses with an increase in tempering temperature and 427 ° C. (7
It is considered that the newly generated stress increases with the temperature due to the decomposition of the retained austenite and the thermal stress generated during cooling after tempering. 4) After heating at 950 to 1100 ° C. for 1 to 2 hours in a heating furnace for uniform heating and then cooling by blast cooling, to minimize residual stress while maintaining excellent wear resistance, tempering is performed. Suitably, the temperature is about 427 ° C (700K).
【００１５】[0015]
【発明の効果】以上説明したように、本発明の耐衝撃摩
耗用高クロム鋳鉄鋳物の製造方法によれば、焼戻し温度
を従来の高温焼戻しと低温焼戻しのほぼ中間としたの
で、硬さを犠牲にすることなく、かつ長時間の熱処理を
必要とせずに、残留応力を最小にすることができる。As described above, according to the method of manufacturing a high chromium cast iron casting for impact resistance according to the present invention, the tempering temperature is set at almost the middle between the conventional high temperature tempering and low temperature tempering, so that the hardness is sacrificed. And the residual stress can be minimized without requiring prolonged heat treatment.
【図１】各テストピースの焼戻し温度とマクロ硬さの関
係を示す説明図である。FIG. 1 is an explanatory diagram showing a relationship between a tempering temperature and a macro hardness of each test piece.
【図２】各テストピースの焼戻し温度と引張強さの関係
を示す説明図である。FIG. 2 is an explanatory diagram showing a relationship between a tempering temperature and a tensile strength of each test piece.
【図３】各テストピースの焼戻し温度と吸収エネルギー
の関係を示す説明図である。FIG. 3 is an explanatory diagram showing the relationship between the tempering temperature and absorbed energy of each test piece.
【図４】各テストピースの焼戻し温度と衝撃摩耗量の関
係を示す説明図である。FIG. 4 is an explanatory diagram showing the relationship between the tempering temperature of each test piece and the amount of impact wear.
【図５】残留応力の測定方法を示す斜視図である。FIG. 5 is a perspective view showing a method for measuring a residual stress.
【図６】各テストピースの焼戻し温度と残留応力の関係
を示す説明図である。FIG. 6 is an explanatory diagram showing a relationship between a tempering temperature and a residual stress of each test piece.
【図７】各テストピースのマクロ硬さと衝撃摩耗量の関
係を示す説明図である。FIG. 7 is an explanatory diagram showing the relationship between the macro hardness of each test piece and the amount of impact wear.
─────────────────────────────────────────────────────
────────────────────────────────────────────────── ───
【手続補正書】[Procedure amendment]
【提出日】平成１１年３月１６日[Submission date] March 16, 1999
【手続補正１】[Procedure amendment 1]
【補正対象書類名】明細書[Document name to be amended] Statement
【補正対象項目名】全文[Correction target item name] Full text
【補正方法】変更[Correction method] Change
【補正内容】[Correction contents]
【書類名】 明細書[Document Name] Statement
【発明の名称】 耐衝撃摩耗用高クロム鋳鉄鋳物の製造
方法Patent application title: Method for producing high chromium cast iron casting for impact wear resistance
【特許請求の範囲】[Claims]
【請求項２】 前記耐衝撃摩耗用高クロム鋳鉄鋳物が１
ｗｔ％以下のＮｉ，Ｍｏ及びＶをそれぞれ含有すること
を特徴とする請求項１記載の耐衝撃摩耗用高クロム鋳鉄
鋳物の製造方法。 2. A high chromium cast iron casting for impact wear resistance comprising:
Claim 1 Symbol placement method for producing a high chromium cast iron foundry impact wear of, characterized in that it contains wt% or less of Ni, Mo and V, respectively.
【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION
【０００１】[0001]
【発明の属する技術分野】本発明は、破砕機や粉砕機等
の耐摩耗部品である打撃板、衝突板、ライナ等の耐衝撃
摩耗用高クロム鋳鉄鋳物の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a high chromium cast iron product for impact wear such as impact plates, impact plates, liners, etc., which are wear components such as crushers and crushers.
【０００２】[0002]
【従来の技術】通常、耐衝撃摩耗用高クロム鋳鉄鋳物
は、Ｃ ２．０〜３．５ｗｔ％、Ｓｉ０．５〜１．５ｗ
ｔ％、Ｍｎ ０．５〜１．５ｗｔ％、Ｃｒ ２０〜３５
ｗｔ％及び残部がＦｅと不可避不純物からなり、硬さが
ＨＲＣ（ロックウエル硬さのＣスケール）５８以上のも
のが用いられている。従来、耐衝撃摩耗用高クロム鋳鉄
鋳物は、重量１００ｋｇ以下の小物製品に限り鋳放しの
まま使用されることがあるが、この方法では、型ばらし
時の冷却が不均一になると組織的なばらつきを生じるた
め、鋳造後にオーステナイト化温度（９００〜１１００
℃）に１〜２時間保持する不安定化熱処理を行った後、
約５０〜１５０℃／ｍｉｎ（約９００〜５００℃の間）
の冷却速度で衝風冷却し、基地組織を硬いマルテンサイ
トを主体としたものとする空気焼入れ処理（TE.Norman,
K.Rohring：Autbereitungs-Technik(1970)6 356、 W.Fa
irhurst, K.Roring：Foundry Trade Journal 136(1974)
685 、 R.S.Jackson：British Foundrymen 67(1974)34
、 G.J.Cor：Foundry Trade Journal 158(1985)480参
照）したり、空気焼入れ処理後に２００〜３５０℃程度
の温度での低温焼戻し処理したり、又は６００℃以上の
温度での高温焼戻し処理したりして製造されている（先
行技術文献として、特開昭５６−４７５４５号公報、特
開昭６０−２１３２３号公報、特開昭６２−１８５８２
５号公報、特開昭５７−８９４５３号公報、特開昭５９
−１２９７２０号公報等がある。）。2. Description of the Related Art Usually, a high chromium cast iron casting for impact wear resistance is composed of 2.0 to 3.5 wt% of C and 0.5 to 1.5 watts of Si.
t%, Mn 0.5-1.5 wt%, Cr 20-35
A material having a wt% and balance of Fe and unavoidable impurities and having a hardness of HRC (C scale of Rockwell hardness) of 58 or more is used. Conventionally, high-chromium cast iron castings for impact wear are often used as-cast only for small products weighing 100 kg or less. However, this method requires systematic dispersion when the cooling during unmolding becomes uneven. Austenitic temperature (900 to 1100) after casting.
C) for 1-2 hours.
About 50-150 ° C / min (between about 900-500 ° C)
Air quenching treatment to cool the base structure with hard martensite as the main component (TE. Norman,
K. Rohring: Autbereitungs-Technik (1970) 6 356, W. Fa
irhurst, K. Roring: Foundry Trade Journal 136 (1974)
685, RSJackson: British Foundrymen 67 (1974) 34
GJCor: Foundry Trade Journal 158 (1985) 480), after air quenching, low-temperature tempering at a temperature of about 200 to 350 ° C, or high-temperature tempering at a temperature of 600 ° C or more. It is manufactured (as prior art documents, JP-A-56-47545, JP-A-60-21323, JP-A-62-15852).
No. 5, JP-A-57-89453, JP-A-57-89453
No. 129720. ).
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、従来の
空気焼入れ処理による耐衝撃摩耗高クロム鋳鉄鋳物の製
造方法では、オーステナイトを多く残留させた場合、鋳
物の形状や大きさによっては、製造時や使用時に鋳物が
変形したり割れる不具合がある。一方、上記空気焼入れ
処理後に焼戻しを行う場合には、残留応力が軽減され、
かつ、耐摩耗性が調整されて上述した不具合は解消され
るが、高温焼戻し処理を施す場合、硬さが低下し、耐用
寿命が短くなり、又、低温焼戻し処理を行う場合、耐用
寿命が長くなるものの、処理に長時間を要し、それでも
十分に残留応力を下げることができない不具合がある。
そこで、本発明は、硬さを犠牲にすることなく、かつ熱
処理に長時間を必要とすることなく残留応力を最小にし
得る耐衝撃摩耗高クロム鋳鉄鋳物の製造方法を提供する
ことを目的とする。However, according to the conventional method for producing a high-abrasion-resistant high-chromium cast iron casting by air quenching, when a large amount of austenite remains, depending on the shape and size of the casting, the production and use of the casting may be difficult. There is a problem that the casting is sometimes deformed or cracked. On the other hand, when tempering is performed after the air quenching treatment, the residual stress is reduced,
In addition, although the above-mentioned problem is solved by adjusting the wear resistance, when performing high-temperature tempering, the hardness is reduced, the service life is shortened, and when performing low-temperature tempering, the service life is increased. However, there is a problem that the treatment requires a long time, and the residual stress cannot be sufficiently reduced.
Therefore, an object of the present invention is to provide a method for producing an impact-resistant high chromium cast iron casting that can minimize residual stress without sacrificing hardness and without requiring a long time for heat treatment. .
【０００４】[0004]
【課題を解決するための手段】前記課題を解決するた
め、本発明の耐衝撃摩耗高クロム鋳鉄鋳物の製造方法
は、Ｃ ２．０〜３．５ｗｔ％、Ｓｉ ０．５〜１．５
ｗｔ％、Ｍｎ ０．５〜２．５ｗｔ％、Ｃｒ ２０〜３
５ｗｔ％及び残部がＦｅと不可避不純物からなり、硬さ
がＨＲＣ５８以上の耐衝撃摩耗用高クロム鋳鉄鋳物の製
造に際し、鋳造物を加熱炉中で９５０〜１１００℃の温
度で均一加熱し、常温まで約１００℃／ｍｉｎの冷却速
度で衝風冷却した後、４００〜４５０℃の温度で８〜１
２時間保持して焼戻すことを特徴とする。又、前記耐衝
撃摩耗用高クロム鋳鉄鋳物は、１ｗｔ％以下のＮｉ，Ｍ
ｏ及びＶをそれぞれ含有していることが好ましい。SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a method for producing an impact-resistant and high-chromium cast iron casting according to the present invention comprises: 2.0 to 3.5 wt% of C and 0.5 to 1.5% of Si.
wt%, Mn 0.5-2.5wt%, Cr 20-3
5% by weight and the balance of Fe and inevitable impurities, the hardness of which is HRC58 or more, when manufacturing a high chromium cast iron casting for impact resistance, the casting is uniformly heated in a heating furnace at a temperature of 950 to 1100 ° C. after air-blast cooling at a cooling rate of about 100 ℃ / min, 8~1 at a temperature of 400 to 4 50 ° C.
It is characterized by holding for 2 hours and tempering. In addition, the high chromium cast iron casting for impact wear resistance contains 1 wt% or less of Ni, M
It preferably contains o and V, respectively.
【０００５】加熱炉中での鋳造物の加熱温度が９５０℃
未満であると、空気焼入れ処理後の硬さが低くなり、１
１００℃を超えると、残留オーステナイトが多くなり、
やはり硬さが低下する。好ましい加熱温度は、９５０〜
１０５０℃である。冷却速度が約１００℃／ｍｉｎから
外れると、焼割れが生じたり、逆に焼入れ不良となる。
焼戻し温度が４００℃未満であると、残留応力が短時間
のうちに十分低減されず、鋳物の製造時や使用中に割れ
を生じることがある。一方、４５０℃を超えると、硬さ
が低下し耐用寿命も短くなる。焼戻しの加熱保持時間が
８時間未満であると、十分な焼戻し効果が得られず、１
２時間を超えると、硬さが低下してくるため、耐用寿命
が短くなる。耐衝撃摩耗用高クロム鋳鉄鋳物がＮｉ，Ｍ
ｏ及びＶを含有すると、焼入れ性や耐用寿命が改善され
る。しかし、それぞれの含有量が１ｗｔ％を超えると、
焼入れ性が必要以上に上がり、割れが生じることがある
と共に、材料のコストを上げる。好ましいそれぞれの含
有量は、０．５〜１．０ｗｔ％である。一方、耐衝撃摩
耗用高クロム鋳鉄鋳物のＣｒの含有量は、２０〜３５ｗ
ｔ％が好ましかった。The heating temperature of the casting in the heating furnace is 950 ° C.
If it is less than 1, the hardness after the air quenching becomes low,
When the temperature exceeds 100 ° C., retained austenite increases,
After all hardness decreases. The preferred heating temperature is 950 to
1050 ° C. If the cooling rate deviates from about 100 ° C./min, quenching cracks occur, and conversely, quenching failure occurs.
If the tempering temperature is lower than 400 ° C., the residual stress is not sufficiently reduced in a short time, and cracks may occur during the production or use of the casting. On the other hand, if it exceeds 4 50 ° C., it is shortened reduced service life hardness. Tempering heating holding time
If the time is less than 8 hours, a sufficient tempering effect cannot be obtained and 1
If the time exceeds 2 hours, the hardness decreases, and the useful life is shortened. High chromium cast iron casting for impact wear resistance is Ni, M
When o and V are contained, the hardenability and the service life are improved. However, when the content of each exceeds 1 wt%,
The hardenability is increased more than necessary, cracks may occur, and the cost of the material is increased. The preferred content of each is 0.5 to 1.0 wt%. On the other hand, the Cr content of the high chromium cast iron casting for impact resistance is 20 to 35 watts.
t% was preferred.
【０００６】[0006]
【発明の実施の形態】以下、本発明の実施の形態につい
て具体的な実施例１及び比較例１〜６を参照して説明す
る。 実施例１、比較例１〜６ 先ず、共晶成分に近い３ｗｔ％Ｃ−２５ｗｔ％Ｃｒ系の
高クロム鋳鉄を得るため、銑鉄、ＳＳ棒鋼、フェロクロ
ム、フェロマンガン及びフェロシリコンを所要量ずつ高
周波誘導炉を用いて溶解し、溶け落ち後溶湯を約１３９
７℃（１６７０Ｋ）の温度に昇温して取鍋内にて１２９
７℃（１５７０Ｋ）になった時点で、ＪＩＳ Ｇ ０３
０７供試材（ａ）に規定されている鋳込み重量約２０ｋ
ｇを各テストピース用鋳型に鋳込んだ。冷却後、押湯を
切除した各供試材を大気雰囲気の加熱炉中において１０
５０℃（１３２３Ｋ）の温度で２時間保持して均一加熱
処理した。熱処理後の冷却方法は衝風冷却であり、半冷
温度と半冷時間から求めた平均冷却速度は、約１００℃
／ｍｉｎであった。次いで、熱処理後の各供試材を未処
理、加熱炉中において２００〜７００℃（４７３〜９７
３Ｋ）の範囲で１００℃の温度間隔で１０時間保持した
後、炉外で自然放冷する焼戻しを行って実施例１（焼戻
し温度４００℃）、比較例１（未処理）、比較例２〜６
（焼戻し温度２００℃，３００℃，５００℃，６００
℃，７００℃）の供試材を得た。各供試材の化学成分と
熱処理条件を表１に示す。BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, will be described with reference to specific examples 1及 beauty Comparative Example 1-6 An embodiment of the present invention. Example 1, Comparative Examples 1 to 6 First, in order to obtain a 3% by weight C-25% by weight Cr-based high chromium cast iron close to the eutectic component, high frequency induction of pig iron, SS bar, ferrochrome, ferromanganese, and ferrosilicon by required amounts. Melt using a furnace, and after melting down, add about 139
The temperature was raised to a temperature of 7 ° C (1670K) and 129 was set in the ladle.
When the temperature reaches 7 ° C. (1570K), JIS G 03
07 Casting weight specified in test material (a) about 20k
g was cast into each test piece mold. After cooling, each specimen from which the feeder was cut was placed in a heating furnace in an air atmosphere for 10 minutes.
It was kept at a temperature of 50 ° C. (1323 K) for 2 hours to perform a uniform heat treatment. The cooling method after the heat treatment is blast cooling, and the average cooling rate obtained from the half-cooling temperature and half-cooling time is about 100 ° C.
/ Min. Next, each of the test materials after the heat treatment was untreated, and was heated at 200 to 700 ° C. (473 to 97 ° C.) in a heating furnace.
After holding for 10 hours at a temperature interval of 100 ° C. within the range of 3 K), tempering was performed by allowing the material to cool naturally outside the furnace, and the results were obtained in Example 1 ( tempering temperature: 400 ° C.) , Comparative Example 1 (untreated), and Comparative Examples 2 to 2. 6
(Tempering temperature 200 ° C, 300 ° C, 500 ° C, 600
, 700 ° C). Table 1 shows the chemical components and heat treatment conditions of each test material.
【０００７】[0007]
【表１】 [Table 1]
【０００８】次に、各供試材から所定のテストピースを
切断採取し、マクロ硬さの測定、引張試験、衝撃試験、
衝撃摩耗試験及び残留応力の測定を行った。マクロ硬さ
の測定は、ロックウエル硬度計のＣスケールにて各テス
トピースの切断面を約２０点計測し、その平均値を求め
たところ、図１に示すようになった。図１から、均一加
熱処理後の硬さは、ＨＲＣ６５程度であるが、焼戻し温
度が、高くなるにつれて硬さがわずかに下がり、３９７
℃（６７０Ｋ）近辺でわずかに二次硬化した後、基地中
の残留オーステナイトの分解が顕著になるため急激に下
がり、６９７℃（９７０Ｋ）を超えるとＨＲＣ４０程度
になっていることがわかる。Next, a predetermined test piece is cut and sampled from each test material, and a macro hardness measurement, a tensile test, an impact test,
An impact wear test and measurement of residual stress were performed. The measurement of the macro hardness was performed by measuring about 20 points on the cut surface of each test piece on a C scale of a Rockwell hardness tester, and the average value was obtained. The result was as shown in FIG. From FIG. 1, the hardness after the uniform heat treatment is about HRC65, but the hardness decreases slightly as the tempering temperature increases,
It can be seen that, after a slight secondary hardening near ℃ (670K), the decomposition of the retained austenite in the matrix becomes remarkable, so that the temperature drops sharply, and when it exceeds 697 ° C (970K), the HRC becomes about 40.
【０００９】引張試験は、５ｍｍの径で平行部長さ２５
ｍｍの各テストピースを用い、０．５ｍｍ／ｍｉｎの定
速ひずみで行ない、破断時の引張強度を調べたところ、
図２に示すようになった。図２から、引張強度は、７０
０〜９００ＭＰａであるが、焼戻し温度との相関がない
ことがわかる。[0009] The tensile test was conducted with a diameter of 5 mm and a parallel part length of 25.
Using each test piece of 0.5 mm / min at a constant speed of 0.5 mm / min, and examining the tensile strength at break,
As shown in FIG. From FIG. 2, the tensile strength is 70
Although it is 0 to 900 MPa, it is understood that there is no correlation with the tempering temperature.
【００１０】衝撃試験は、１０×１０×５５ｍｍのノッ
チなし形状の各テストピースで、荷重５ｋｇのシャルピ
ー試験機を用い、破断時の吸収エネルギーを調べたとこ
ろ、図３に示すようになった。図３から、焼戻し温度
が、５００℃（７７３Ｋ）でわずかに吸収エネルギーが
下がり、６００℃（８７３Ｋ）で再び上昇しているが、
いずれの温度でもその値は低く２〜３Ｊで、焼戻し温度
と靭性に大きな相関がないことがわかる。[0010] In the impact test, the absorbed energy at the time of breaking was measured using a Charpy tester with a load of 5 kg on each test piece having a notch shape of 10 x 10 x 55 mm, and the results are as shown in Fig. 3. From FIG. 3, the tempering temperature slightly decreased at 500 ° C. (773 K) and increased again at 600 ° C. (873 K).
At any temperature, the value was as low as 2 to 3 J, indicating that there is no great correlation between the tempering temperature and the toughness.
【００１１】衝撃摩耗試験は、インペラーブレーカ型の
試験機を用い、約３００ｋｇの石を破砕し、破砕前後の
各テストピース（打撃板）の重量より摩耗減量を測定し
たところ、図４に示すようになった。図４から、焼戻し
温度が高くなるにつれて摩耗量が増加し、特に５００℃
（７７３Ｋ）を超えると急激に摩耗量が増えていること
がわかる。なお、試験に用いた石は、ＳｉＯ2 を約７８
ｗｔ％含有した硅石で、粒径が５〜２０ｍｍである。
又、打撃板の周速は２９ｍ／ｓ、打撃板と衝突板との間
隔は１５ｍｍである。In the impact wear test, an impeller breaker type testing machine was used to crush about 300 kg of stone, and the wear loss was measured from the weight of each test piece (strike plate) before and after crushing, as shown in FIG. Became. From FIG. 4, it can be seen that the wear amount increases as the tempering temperature increases,
(773K), it can be seen that the abrasion amount rapidly increases. The stone used in the test was SiO 2 of about 78
It is silica stone containing wt%, and the particle size is 5 to 20 mm.
The peripheral speed of the striking plate is 29 m / s, and the distance between the striking plate and the collision plate is 15 mm.
【００１２】残留応力の測定は、図５に示すように、直
径３０ｍｍの球状の鋳物(casting ball)の表面４ケ所に
ひずみゲージ(strain gauge)を貼り付け、熱がかからな
いように注意しながらワイヤーソーを用いて切断し、最
後に約１０×１０×２ｔｍｍの小片になった時のひずみ
量をデジタル静ひずみ計によって行ったところ、図６に
示すようになった。図６から、鋳込み直後に型ばらしし
て急冷したもの(Shake out immediately and rapid coo
ling in air)と、砂型中で徐冷後に型ばらししたもの(S
low cooling in the sand mold) のいずれも４２７〜４
７７℃（７００〜７５０Ｋ）の焼戻し温度で、残留応力
が最小値を示していることがわかる。なお、ひずみゲー
ジは、ゲージ長１ｍｍ、ゲージ抵抗１２０Ω、ゲージ率
２．０６（東京測器研究所 ＦＲＡ−１−１１−１
Ｌ）、接着剤は、シアノアクリレート系（同社のＣ
Ｎ）、コーティング剤は、アラルダイトラピッド（昭和
高分子）を用いた。As shown in FIG. 5, the measurement of the residual stress is performed by attaching strain gauges to four surfaces of a spherical casting (casting ball) having a diameter of 30 mm and paying attention to the heat while avoiding heat. Cutting was performed using a saw, and finally, when a small piece of about 10 × 10 × 2 tmm was obtained, the amount of strain was measured by a digital static strain meter, and the result was as shown in FIG. FIG. 6 shows that the mold was separated immediately after casting and was rapidly cooled (Shake out immediately and rapid coo
ling in air)
low cooling in the sand mold)
It can be seen that at a tempering temperature of 77 ° C. (700 to 750 K), the residual stress shows a minimum value. In addition, the strain gauge has a gauge length of 1 mm, a gauge resistance of 120Ω, and a gauge factor of 2.06 (FRA-1-11-1, Tokyo Sokki Laboratory).
L), adhesives are cyanoacrylate-based (C
N), Araldiprapid (Showa Kobunshi) was used as the coating agent.
【００１３】一方、マクロ硬さと衝撃摩耗量との関係を
調べるため、前述したインペラーブレーカ型の試験機を
用い、マクロ硬さの異なる各テストピースの衝撃摩耗量
を同様に測定したところ、従前のデータをも含めた図７
に示すようになった。図７において□は鋳放しのまま、
○は空気焼入れ処理、△は焼戻し処理のテストピースを
示し、又、実線はオーステナイトが０〜６０ｗｔ％、破
線はオーステナイトが７０〜９０ｗｔ％のテストピース
を示す。図７から、マクロ硬さと衝撃摩耗量には相関が
あり、マクロ硬さが高くなるにつれて衝撃摩耗量が低下
することがわかる。On the other hand, in order to examine the relationship between the macro hardness and the impact wear amount, the impact wear amount of each test piece having a different macro hardness was measured in the same manner using the impeller breaker type testing machine described above. Fig. 7 including data
It became as shown in. In FIG. 7, □ is as cast,
○ indicates a test piece of the air quenching treatment, and △ indicates a test piece of the tempering treatment, and the solid line indicates a test piece of 0 to 60 wt% of austenite, and the broken line indicates a test piece of 70 to 90 wt% of austenite. FIG. 7 shows that there is a correlation between the macro hardness and the impact wear amount, and the impact wear amount decreases as the macro hardness increases.
【００１４】上述したことから次のことが言える。 １）マクロ硬さは、焼戻し温度を上げるにつれて低下
し、焼戻し温度が４２７℃（７００Ｋ）を超えると、急
激に下がる。しかし、引張強度及び靭性は大きな変化が
無く、焼戻し温度の影響をほとんど受けない。 ２）衝撃摩耗量と焼戻し温度には相関があり、焼戻し温
度を上げるにつれてわずかに増加し、焼戻し温度が４２
７℃（７００Ｋ）を超えると急激に増加する。 ３）残留応力は、焼戻し温度を上げるにつれて減少する
が、焼戻し温度が４２７〜４７７℃（７００〜７５０
Ｋ）で最小値をとり、それ以後増加する。これは、焼戻
し温度の上昇と共に応力緩和が進むのと、４２７℃（７
００Ｋ）以上で生じる残留オーステナイトの分解及び焼
戻し後の冷却中に生じる熱応力により、新たに発生する
応力が温度と共に増加するためと考えられる。 ４）加熱炉中で９５０〜１１００℃の温度で１〜２時間
保持して均一加熱処理してから衝風冷却した後に優れた
耐摩耗性を保ったまま残留応力を最小にするには、焼戻
し温度を約４２７℃（７００Ｋ）にするのが適当であ
る。The following can be said from the above. 1) The macro hardness decreases as the tempering temperature increases, and sharply decreases when the tempering temperature exceeds 427 ° C (700K). However, the tensile strength and toughness do not change significantly and are hardly affected by the tempering temperature. 2) There is a correlation between the amount of impact wear and the tempering temperature, which increases slightly as the tempering temperature increases,
When the temperature exceeds 7 ° C. (700 K), it rapidly increases. 3) The residual stress decreases as the tempering temperature increases, but when the tempering temperature is 427 to 477 ° C (700 to 750 ° C).
K) takes the minimum value and increases thereafter. This is because stress relaxation progresses with an increase in tempering temperature and 427 ° C. (7
It is considered that the newly generated stress increases with the temperature due to the decomposition of the retained austenite and the thermal stress generated during cooling after tempering. 4) After heating at 950 to 1100 ° C. for 1 to 2 hours in a heating furnace for uniform heating and then cooling by blast cooling, to minimize residual stress while maintaining excellent wear resistance, tempering is performed. Suitably, the temperature is about 427 ° C (700K).
【００１５】[0015]
【発明の効果】以上説明したように、本発明の耐衝撃摩
耗用高クロム鋳鉄鋳物の製造方法によれば、焼戻し温度
を従来の高温焼戻しと低温焼戻しのほぼ中間としたの
で、硬さを犠牲にすることなく、かつ長時間の熱処理を
必要とせずに、残留応力を最小にすることができる。As described above, according to the method of manufacturing a high chromium cast iron casting for impact resistance according to the present invention, the tempering temperature is set at almost the middle between the conventional high temperature tempering and low temperature tempering, so that the hardness is sacrificed. And the residual stress can be minimized without requiring prolonged heat treatment.
【図面の簡単な説明】[Brief description of the drawings]
【図１】各テストピースの焼戻し温度とマクロ硬さの関
係を示す説明図である。FIG. 1 is an explanatory diagram showing a relationship between a tempering temperature and a macro hardness of each test piece.
【図２】各テストピースの焼戻し温度と引張強さの関係
を示す説明図である。FIG. 2 is an explanatory diagram showing a relationship between a tempering temperature and a tensile strength of each test piece.
【図３】各テストピースの焼戻し温度と吸収エネルギー
の関係を示す説明図である。FIG. 3 is an explanatory diagram showing the relationship between the tempering temperature and absorbed energy of each test piece.
【図４】各テストピースの焼戻し温度と衝撃摩耗量の関
係を示す説明図である。FIG. 4 is an explanatory diagram showing the relationship between the tempering temperature of each test piece and the amount of impact wear.
【図５】残留応力の測定方法を示す斜視図である。FIG. 5 is a perspective view showing a method for measuring a residual stress.
【図６】各テストピースの焼戻し温度と残留応力の関係
を示す説明図である。FIG. 6 is an explanatory diagram showing a relationship between a tempering temperature and a residual stress of each test piece.
【図７】各テストピースのマクロ硬さと衝撃摩耗量の関
係を示す説明図である。FIG. 7 is an explanatory diagram showing the relationship between the macro hardness of each test piece and the amount of impact wear.
Claims (3)
５〜１．５ｗｔ％、Ｍｎ ０．５〜２．５ｗｔ％、Ｃｒ
２０〜３５ｗｔ％及び残部がＦｅと不可避不純物から
なり、硬さがＨＲＣ５８以上の耐衝撃摩耗用高クロム鋳
鉄鋳物の製造に際し、鋳造物を加熱炉中で９５０〜１１
００℃の温度で均一加熱し、常温まで約１００℃／ｍｉ
ｎの冷却速度で衝風冷却した後、４００〜５５０℃の温
度で焼戻すことを特徴とする耐衝撃摩耗用高クロム鋳鉄
鋳物の製造方法。C. 2.0 to 3.5 wt% of C, and 0.1% of Si.
5 to 1.5 wt%, Mn 0.5 to 2.5 wt%, Cr
In producing a high chromium cast iron casting for impact wear having a hardness of HRC 58 or more, the casting is 950-11% in a heating furnace.
Heat uniformly at a temperature of 00 ° C, and to about 100 ° C / mi
A method for producing a high chromium cast iron casting for impact resistance, comprising: cooling by impingement at a cooling rate of n and tempering at a temperature of 400 to 550 ° C.
間とすることを特徴とする請求項１記載の耐衝撃摩耗用
高クロム鋳鉄鋳物の製造方法。2. The method for producing a high chromium cast iron product for impact wear resistance according to claim 1, wherein the heat holding time of the tempering is 5 to 15 hours.
ｗｔ％以下のＮｉ，Ｍｏ及びＶをそれぞれ含有すること
を特徴とする請求項１又は２記載の耐衝撃摩耗用高クロ
ム鋳鉄鋳物の製造方法。3. The high-chromium cast iron casting for impact wear resistance according to claim 1.
3. The method for producing a high chromium cast iron product for impact wear resistance according to claim 1, wherein the content of each of Ni, Mo and V is not more than wt%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5621398A JPH11236615A (en) | 1998-02-20 | 1998-02-20 | Manufacturing method of high chromium cast iron casting for impact wear resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP5621398A JPH11236615A (en) | 1998-02-20 | 1998-02-20 | Manufacturing method of high chromium cast iron casting for impact wear resistance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH11236615A true JPH11236615A (en) | 1999-08-31 |
Family
ID=13020837
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP5621398A Pending JPH11236615A (en) | 1998-02-20 | 1998-02-20 | Manufacturing method of high chromium cast iron casting for impact wear resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH11236615A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101893033B (en) | 2009-05-19 | 2012-08-22 | 天润曲轴股份有限公司 | Bulb ferroalloy crankshaft |
| CN105088055A (en) * | 2015-06-26 | 2015-11-25 | 南京梅山冶金发展有限公司 | Wear-resisting hammer head for hammer type breaking machine and production method of wear-resisting hammer head |
| CN110512152A (en) * | 2019-08-23 | 2019-11-29 | 徐州东坤耐磨材料有限公司 | A kind of high-chromium wear-resistant steel ball and preparation method thereof |
| CN110527792A (en) * | 2019-08-26 | 2019-12-03 | 武汉科技大学 | Reduce the tempering method of residual stress |
| CN114657451A (en) * | 2022-03-29 | 2022-06-24 | 西安热工研究院有限公司 | Hypereutectic high-chromium cast iron and suspension and modification composite treatment method thereof |
| CN115287420A (en) * | 2022-08-26 | 2022-11-04 | 谷城大成机械有限公司 | A kind of metal casting heat treatment air cooling quenching and tempering process |
| JP2023160133A (en) * | 2022-04-21 | 2023-11-02 | 古河機械金属株式会社 | Softening heat treatment method for high chromium cast iron |
-
1998
- 1998-02-20 JP JP5621398A patent/JPH11236615A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101893033B (en) | 2009-05-19 | 2012-08-22 | 天润曲轴股份有限公司 | Bulb ferroalloy crankshaft |
| CN105088055A (en) * | 2015-06-26 | 2015-11-25 | 南京梅山冶金发展有限公司 | Wear-resisting hammer head for hammer type breaking machine and production method of wear-resisting hammer head |
| CN110512152A (en) * | 2019-08-23 | 2019-11-29 | 徐州东坤耐磨材料有限公司 | A kind of high-chromium wear-resistant steel ball and preparation method thereof |
| CN110527792A (en) * | 2019-08-26 | 2019-12-03 | 武汉科技大学 | Reduce the tempering method of residual stress |
| CN114657451A (en) * | 2022-03-29 | 2022-06-24 | 西安热工研究院有限公司 | Hypereutectic high-chromium cast iron and suspension and modification composite treatment method thereof |
| JP2023160133A (en) * | 2022-04-21 | 2023-11-02 | 古河機械金属株式会社 | Softening heat treatment method for high chromium cast iron |
| CN115287420A (en) * | 2022-08-26 | 2022-11-04 | 谷城大成机械有限公司 | A kind of metal casting heat treatment air cooling quenching and tempering process |
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