CN1003430B

CN1003430B - High hardness, wear resistance and non-preheating surfacing electrode

Info

Publication number: CN1003430B
Application number: CN86101106.6A
Authority: CN
Inventors: 翟厚仁; 彭丁升; 陈利民; 彭桂英; 张清辉; 陈玉斌
Original assignee: JIANGLU MACHINERY FACTORY; Xiangtan University
Current assignee: JIANGLU MACHINERY FACTORY; Xiangtan University
Priority date: 1986-01-18
Filing date: 1986-01-18
Publication date: 1989-03-01
Also published as: CN86101106A

Abstract

The high-hardness wear-resistant surfacing electrode is not preheated, the HRC of the surfacing layer at normal temperature is more than or equal to 58, preheating is not carried out, and the surfacing layer has no cracks. The main raw materials are as follows by weight percent: 13 to 25 parts of marble, 2 to 8 parts of fluorite, 5 to 20 parts of high-carbon ferrochrome, 0.5 to 3 parts of titanium dioxide, 3 to 8 parts of medium-carbon ferromanganese, 8 to 20 parts of ferromolybdenum, 1.5 to 6 parts of tungsten powder, 10 to 20 parts of ferrovanadium, 0.8 to 4 parts of graphite, 0.8 to 2 parts of quartz and 2 to 3 parts of ferrotitanium. The cold surfacing method is suitable for cold surfacing on low and medium carbon steel and low and medium alloy structural steel; no preheating is needed before welding, and no heat treatment can be carried out after welding.

Description

High-hardness wear-resistant non-preheating surfacing welding rod

In the surfacing process, surfacing materials with high hardness (HRC is more than 50) in China and countries all over the world need to be preheated, slow cooling is needed after welding, even heat treatment is carried out after welding, otherwise, surfacing metal inevitably has cracks, and particularly, when surfacing is carried out on parts with large rigidity, the cracks are still difficult to eliminate sometimes even if the welding process measures are adopted.

For example, the following two electrodes used in the united states have the following main components and properties: (data obtained from "selection of application of hard surfacing alloy and surfacing method thereof" published in 1973, 6 months, compiled by Shanghai scientific and technical information):

numbering	C	Mn	Si	Cr	W	Mo	V	Preheating temperature	Thickness of welding layer
										1	0.35	0.3-0.4	4.75-5.25	3.0-3.50	2.5-3.00	0.3-0.4	510℃	HRC54-57
2	0.85	0.5	0.7	4.0	6.0	5.0	2.0	Is required to be preheated	HRC55-60

The workpiece must be preheated before the surfacing welding of the two welding rods.

Therefore, preheating the high hardness weld overlay before welding and heat treatment after welding have long been a common rule for reducing the tendency of cracking. Otherwise, the high-hardness surfacing electrode cannot avoid cracks during surfacing at normal temperature.

The invention ensures that the austenite is transformed to martensite at a certain stage of the surfacing metal which is most easy to form cracks in the cooling process in the range of the welding cooling speed by selecting the reasonable content of various alloy elements in the metal of the welding layer so as to reduce or even eliminate the tensile stress in the welding layer, thereby achieving the purpose of reducing (even eliminating) the tensile stressTo avoid) the generation of cracks. Because two factors are mainly responsible for the phase transformation process and the texture of the layer, namely the cooling rate and the composition of the layer. The cooling rate is constant under certain welding conditions and is determined mainly by its composition. Through a large number of experimental researches, the following components in percentage by weight of the overlaying layer are adopted to ensure that the hardness after welding reaches HRC_58-62And no cracking:

C	Cr	Mo	W	V	Mn	Si	S	P	Ti
										0.9-1.4	5-7	4-6	4-6	4-6	1.5-2.5	0.4-1.0	≤0.03	≤0.03	0.03-0.08

the welding rod provided by the invention is prepared by a certain welding rod coating component according to a specified coating coefficient, and the welding rod is subjected to surfacing under a specified strict welding specification to obtain the welding layer component.

The welding rod coating comprises the following components in percentage by weight:

marble	Fluorite	High carbon ferrochrome	Titanium white powder	Medium carbon ferromanganese	Ferromolybdenum	Tungsten powder	Vanadium iron	Graphite	Quartz	Ferrotitanium
											13-25	2-8	5-20	0.5-3	3-8	8-20	1.5-6	10-20	0.8-4	0.8-2	2-3

Core wire material: H08A, coating coefficient: 1.0-1.5, welding current type: direct current reverse connection, welding specification: φ 4 (mm) I: 150-200A

The welding rod has the characteristics that no crack is generated when the welding rod is used for surfacing on parts with larger rigidity, the deformation after welding is not large, and the preheating before welding and the heat treatment after welding are not needed.

Example 1: FIG. 1 shows the roll shaft of a single roll crusher in a metallurgical sintering machine with high rigidity. The shaft material is as follows: cast steel No. 35, heat treatment state: hardening and tempering, and size: see figure 1. The welding rod coating comprises the following components: H08A, coating coefficient: 1.0-1.5. The type of welding current: direct current reverse connection, welding specification: φ 4 (mm) I: 150-200A, welding part: the components of the surfacing layer are the same as those of the shaft and the claws. Surfacing at normal temperature, preheating is not needed before welding, heat treatment is not needed after welding, cracks do not appear on the surfacing layer, the normal-temperature hardness HRC of the surfacing layer is more than or equal to 58, the average hardness HV595 is achieved at 500 ℃, and the wear resistance is good. The electrode is currently used in production.

Example 2: fig. 2 is a schematic view of a gear ring of a driving wheel of a certain chariot. Gear ring material: 20CrMnSiNi2, and the strength of the gear ring material: 110-120kg/mm²(HRC 47); ring gear size: see figure 2. The coating composition, core material, coating coefficient, welding current type and welding specification of the welding rod were the same as those of example 1. Surfacing parts: the surface of the gear ring is subjected to one-time surfacing welding with the thickness of 5 mm. The composition of the weld overlay is the same as above. Surfacing at normal temperature, preheating is not needed before welding, heat treatment is not needed after welding, the surfacing layer has no cracks, and the measured hardness HRC is more than or equal to 58. After the gear ring is subjected to build-up welding, the mileage of the gear ring is more than 6000 kilometers after a sports car test at home and abroad at-40 ℃ to 40 ℃. The welding rod has been used in production for more than 5 years, and 600 gear rings are produced in total. No crack appears in domestic and foreign use.

Claims

1. High-hardness, wear-resistant, no-preheat cladding electrode, made from marble, fluorite, high-carbon ferrochrome, titanium dioxide, medium-carbon ferromanganese, ferromolybdenum, tungsten powder, ferrovanadium, graphite, quartz, ferrotitanium, H08A welding core, and water glass. The coating's main raw materials are formulated in the following weight percentages: marble 13-25%, fluorite 2-8%, high-carbon ferrochrome 5-20%, titanium dioxide 0.5-3%, medium-carbon ferromanganese 3-8%, ferromolybdenum 8-20%, tungsten powder 1.5-6%, ferrovanadium 10-20%, graphite 0.8-4%, quartz 0.8-2%, and ferrotitanium 2-3%. Coating coefficient: 1.0-1.5.

2. The non-preheating overlay welding rod according to claim 1, characterized in that the composition of the overlay layer is as follows by weight: carbon 0.9 to 14, chromium 5 to 7, molybdenum 4 to 6, tungsten 4 to 6, vanadium 4 to 6, manganese 1.5 to 2.5, silicon 0.4 to 1.0, sulfur less than or equal to 0.03, phosphorus less than or equal to 0.03, and titanium 0.03 to 0.08.