CN106995903A - A kind of ocean engineering anticorrosion stress-resistant dual phase steel stainless steel wire rope and preparation method - Google Patents

Abstract

The present invention proposes a stress corrosion resistant dual-phase steel stainless steel wire rope for ocean engineering, the raw material steel consists of 25%-28% elemental chromium (Cr), 6%-9% elemental nickel (Ni), 3% by weight. %‑5% element molybdenum (Mo) and iron as the basis composition, with no less than 0.3% nitrogen (N) element for microalloying treatment, adding boron (B) and titanium (Ti) with a content of no more than 0.5% to the steel ), aluminum (Al), vanadium (V), niobium (Nb) in any one or several trace elements. The present invention also proposes a preparation method for the above-mentioned stainless steel wire rope. The stress corrosion resistant duplex steel stainless steel wire rope for marine use of the present invention uses nitrogen microalloyed duplex steel as a raw material, and the prepared steel wire rope has excellent stress resistance strength and corrosion resistance, good processing performance, and has a small diameter. Technological performance, to meet the lifting operation of high pressure and high concentration of salt content in ocean deep water area.

Description

A kind of stress corrosion resistant duplex steel stainless steel wire rope for ocean engineering and its preparation method

technical field

The invention relates to the technical field of new material preparation, in particular to a stress-corrosion-resistant dual-phase steel stainless steel wire rope for marine engineering that is suitable for marine dynamic stress environments and operates in heavy chloride ion mediums that corrode ambient air and liquids.

Background technique

With the continuous development of modern industry, the application of stainless steel wire ropes has shifted from land to sea, such as deep sea exploration and research, deep sea ore mining, and blocking fences for drilling rigs. The marine environment has more harsh corrosive media than the land, so that the materials used in the land are not suitable for the marine environment. The high concentration of chloride ion content and high pressure environment require high-strength steel wire ropes resistant to stress corrosion, which requires high-strength steel wire ropes in such environments Steel wire ropes made of super duplex steel are required in The current 304, 316, and 316L stainless steel wire ropes have insufficient stress corrosion resistance and poor fatigue life, while the point resistance index (PREN=46.8) of the currently used super duplex stainless steel 2507 meets the requirements of index 40. 2507 duplex steel is iron The microstructure of ferrite and austenite each accounts for 50%, has hot and cold workability, easy product processing and saving precious metal nickel, and is suitable for general marine production conditions; however, for marine steel wire ropes must also meet high strength, durability Wear and high fatigue properties, as well as process performance for small diameters.

Contents of the invention

The purpose of the present invention is to propose a stress corrosion resistant duplex stainless steel wire rope for marine engineering and a preparation method thereof, aiming at the application requirements of the current stress corrosion resistant duplex stainless steel wire rope products for the marine environment. The steel wire rope has Excellent stress resistance and corrosion resistance, which can meet the lifting operation of high pressure and high concentration of salt content in deep water areas of the ocean.

In order to achieve the purpose of the present invention, a kind of marine engineering of the present invention uses stress corrosion resistant duplex steel stainless steel wire rope, and its raw material steel is by weight percentage by the element chromium (Cr) of 25%-28%, 6%-9% The elemental nickel (Ni), 3%-5% elemental molybdenum (Mo) and iron are the basic composition, and the microalloying treatment is carried out with not less than 0.3% nitrogen (N) element, and the content is not more than 0.5% boron is added to the steel Any one or several trace elements of (B), titanium (Ti), aluminum (Al), vanadium (V), niobium (Nb).

Preferably, the content of element phosphorus (P) is not more than 0.02%; the content of sulfur (S) is not more than 0.01%.

The present invention also proposes a preparation method for preparing the above-mentioned stress corrosion resistant duplex steel stainless steel wire rope for marine engineering, which includes the steps of:

(S1) Electroslag remelting: Use the slag material equipped with three slag systems (50%-70%) CaF+(20%-40%) Al2O3+(5%-10%) CaO to perform electroslag remelting to obtain fine grain and pure tissue;

(S2) using a forging ratio greater than 4 for billet opening;

(S3) hot-rolled coils, the coils are subjected to high-temperature solution treatment at a heating temperature of 1180°C-1250°C; heat preservation for 2 hours, and cryogenic treatment with liquid nitrogen;

(S4) Steel wire drawing, the drawn steel wire enters the rope winding preparation, reserves 3% pre-deformation, and uses high-frequency heating in the range of 400°C-500°C for stabilization treatment.

(S5) After the rope is formed, low-temperature annealing (450°C-520°C) is used to remove the rope stress and improve the overall passability of the steel rope.

Preferably, in step S1, it also includes adding not more than 0.01% rare earth as the final deoxidizer.

A stress-corrosion resistant dual-phase steel stainless steel wire rope for marine engineering of the present invention uses nitrogen microalloyed dual-phase steel as a raw material, and the prepared steel wire rope has excellent stress resistance strength and corrosion resistance, good processing performance, and small The technical performance of the size and diameter can meet the lifting operation of high pressure and high concentration of salt in the deep water area of the ocean.

Description of drawings

none.

detailed description

Steel wire rope is a product with high fatigue wear resistance and flexibility. The matrix structure is in a fibrous state. When it is applied in a marine high chloride ion corrosion environment under reciprocating force and in contact with pulleys, it must have high fatigue life and wear resistance. Therefore, Fine grain size and pure structure are necessary conditions. Although the pitting index of super duplex steel 2507 is greater than 40, it basically meets the application under different environmental conditions in the ocean. However, the steel wire rope for marine use must also meet high strength, Wear resistance and high fatigue performance, as well as small diameter processing performance. Therefore, starting from the raw material design of materials, high strength and high toughness (and the so-called double-high characteristics) must first be considered. Super dual-phase steel generally obtains high corrosion resistance by reducing carbon and increasing nitrogen. Nitrogen atoms and Carbon atoms have the same characteristics and are interstitial elements, which exist in the grains to strengthen and reduce the overall toughness. For this reason, the microalloying treatment of nitrogen is important; in addition, the scheme designed to obtain fine grains and pure structures , It is also necessary to control harmful elements, combined with a large proportion of deep processing of fibrous tissue, multi-stage heat treatment and other technologies, so as to give the best design solution.

According to the above-mentioned invention principle, a kind of stress corrosion resistant duplex steel stainless steel wire rope for ocean engineering of the present invention, its raw material steel consists of 25%-28% element chromium (Cr), 6%-9% element Nickel (Ni); 3%-5% elements molybdenum (Mo) and iron as the basis composition, microalloying treatment with not less than 0.3% nitrogen (N) element, adding boron (no more than 0.5%) to the steel Any one or several trace elements in B), titanium (Ti), aluminum (Al), vanadium (V), niobium (Nb); in addition, in a preferred embodiment, the element phosphorus (P) in steel The content of sulfur (S) is not more than 0.02%; the content of sulfur (S) is not more than 0.01%.

The preparation method of the present invention for preparing the above-mentioned marine engineering stress corrosion resistant duplex steel stainless steel wire rope is specifically:

(S1) Electroslag remelting: Use the slag material equipped with three slag systems (50%-70%) CaF+(20%-40%) Al2O3+(5%-10%) CaO to perform electroslag remelting to obtain fine grain and pure tissue;

(S2) using a forging ratio greater than 4 for billet opening to obtain high plasticity;

(S3) Hot-rolled coils. In the production of steel wires, the coils must be subjected to high-temperature solution treatment (heating temperature 1180°C-1250°C), heat preservation for 2 hours, and cryogenic treatment with liquid nitrogen;

(S4) Steel wire drawing, the drawn steel wire enters the rope winding preparation, reserves 3% pre-deformation, and uses high-frequency heating in the range of 400°C-500°C for stabilization treatment.

(S5) After the rope is formed, low-temperature annealing (450°C-520°C) is used to remove the rope stress and improve the overall passability of the steel rope.

Preferably, in step S1, it also includes adding not more than 0.01% rare earth as the final deoxidizer.

Specific examples:

Embodiment one:

Microalloy the alloy with nitrogen, add boron and copper, and carry out electroslag remelting according to the above steps. The design content and measured content of elements in the steel are shown in Table 1 below:

Table 1: Chemical composition of steel

The prepared disk element was drawn into a 0.25mm steel wire, and the structure was made into a 1×3 steel wire rope, and the stress corrosion test was carried out. The test results are shown in Table 2 (compared with 316L):

Table 2

Embodiment two:

Microalloy the alloy with nitrogen, add boron, copper, and vanadium, and carry out electroslag remelting according to the above steps. The design content and measured content of elements in the steel are shown in Table 3 below:

Table 3 Chemical Composition of Steel

Draw the prepared disc element into 0.25mm steel wire, make it into a 1×7 steel wire rope, and carry out the stress corrosion test. The test results are shown in Table 4 (compared with 316L):

Table 4

Embodiment three:

Microalloy the alloy with nitrogen, add boron, copper, and aluminum, and carry out electroslag remelting according to the above steps. The design content and measured content of elements in the steel are shown in Table 5 below:

Table 5 Chemical Composition of Steel

The prepared disk element was drawn into a 0.25mm steel wire, and the structure was made into a 3×7 steel wire rope, and the stress corrosion test was carried out. The test results are shown in Table 6 (compared with 316L):

Table 6

A kind of stress corrosion resistant duplex steel stainless steel wire rope for marine engineering of the present invention, the new steel grade of following table 7 is example, its corrosion resistance, the mechanical property (seeing table 8) of steel wire rope, fatigue resistance (seeing table 9) The detection comparison is as follows:

Table 7 Chemical Composition Design of Steel

steel type C Si mn P S Cr Ni Mo N Cu B Ce 2507 0.03 0.4 1.5 0.04 0.03 25 6 3 0.2 new steel 0.01 0.08 0.5 0.02 0.01 25 6.5 4 0.3 0.5 0.003 0.010 Measured 0.007 0.04 0.41 0.0098 0.005 25.3 6.78 4.2 0.32 0.48 0.0018 0.01

2507 pitting index PREN＝46.8, and improved new steel pitting index PREN＝46.8

Table 8: Mechanical Properties of Wire Rope

steel type structure Specification Minimum breaking force/KN 316L 6×7+1WS 2.4mm 4.25 2507 6×7+1WS 2.4mm 6.85 new steel 6×7+1WS 2.4mm 6.65

As shown in Table 8 above, the breaking force of the new steel type and the super duplex steel wire rope are not much different, and both have high strength performance.

Table 9: Fatigue Resistance

steel type Wire Rope Structure Nominal diameter apply tension Fatigue times Breaking force after test 316L 6×7+1WS 2.4 40N 70000 ≥2.45kN 2507 6×7+1WS 2.4 40N 70000 broken wire new steel 6×7+1WS 2.4 40N 70000 ≥5.25kN

As shown in Table 9 above, the nitrogen microalloyed dual-phase steel stainless steel wire rope of the present invention has high strength and high fatigue resistance.

A stress-corrosion resistant dual-phase steel stainless steel wire rope for marine engineering of the present invention uses nitrogen microalloyed dual-phase steel as a raw material, and the prepared steel wire rope has excellent stress resistance strength and corrosion resistance, good processing performance, and small The technical performance of the size and diameter can meet the lifting operation of high pressure and high concentration of salt in the deep water area of the ocean.

The present invention is not limited to the described embodiment, and those skilled in the art can still make some amendments or changes without departing from the spirit of the present invention, that is, within the disclosed scope, so the protection scope of the present invention is defined by the claims range prevails.

Claims (4)

1. a kind of ocean engineering anticorrosion stress-resistant dual phase steel stainless steel wire rope, it is characterised in that its raw steel percentage by weight Than the elemental chromium (Cr) by 25%-28%, 6%-9% elemental nickel (Ni), based on 3%-5% molybdenum (Mo) and iron Composition, microalloy treatment is carried out with nitrogen (N) element not less than 0.3%, add in steel content be not more than 0.5% boron (B), Any one of titanium (Ti), aluminium (Al), vanadium (V), niobium (Nb) or several trace elements.

2. a kind of ocean engineering anticorrosion stress-resistant dual phase steel stainless steel wire rope as claimed in claim 1, it is characterised in that its The content of middle element phosphor (P) is not more than 0.02%；The content of sulphur (S) is not more than 0.01%.

3. a kind of prepare a kind of as claimed in claim 1 or 2 ocean engineering anticorrosion stress-resistant dual phase steel stainless steel wire rope Preparation method, it includes step：

(S1) electroslag remelting：It is equipped with three slag systems (50%-70%) CaF+ (20%-40%) Al2O3+ (5%-10%) CaO Slag charge, carries out electroslag remelting and obtains fine grain and pure tissue；

(S2) it is more than 4 using ratio of forging reduction and carries out cogging；

(S3) hot rolling disk member, disk member carries out higher temperature solid solution, and heating-up temperature is 1180 DEG C -1250 DEG C；Insulation 2 hours, passes through Liquid nitrogen deep processing；

(S4) steel wire drawing, the steel wire after drawing is prepared into wiring, 3% predeformation is reserved, with 400 DEG C -500 of high-frequency heating It is DEG C interval to carry out stabilization processes.

(S5) restrict stress, the overall poker of Winding rope are gone by process annealing (450 DEG C -520 DEG C) after rope shaping.

4. a kind of preparation method of ocean engineering anticorrosion stress-resistant dual phase steel stainless steel wire rope as claimed in claim 3, In step S1, in addition to no more than 0.01% rare earth is added for end-deoxidizer.