Welding method for low-alloy wear-resistant material with carbon equivalent smaller than or equal to 1.1

Abstract

The invention discloses a welding method for a low-alloy wear-resistant material with the carbon equivalent smaller than or equal to 1.1. The welding method comprises the following steps that firstly, impurities and oxide skin on the surface of the wear-resistant material are removed; 2, base metal is preheated before welding, protective gas is used for gas shield welding, the welding material is S307Si, the welding current ranges from 210 A to 280 A, and the welding voltage ranges from 22 V to 31 V; and 3, covering heat preservation with a heat preservation blanket after welding for heat preservation. The method solves the problems that welding seams of wear-resistant material dissimilar steel are cracked and base metal is delayed to crack; the welding strength is high, impact resistance is achieved, and cracking is avoided; implementation is simple, and welding efficiency is high.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dissimilar steel welding, in particular to a welding method of low alloy wear-resistant material with carbon equivalent less than or equal to 1.1. BACKGROUND

[0002] In the conventional welding production practice of wear-resistant materials, we often face a series of difficult problems. Wear-resistant materials have the characteristics of high hardness, and the carbon equivalent is more than 0.6. This high carbon equivalent greatly reduces the weldability of the material. In the welding process, frequent weld cracking or delayed cracking of the base material and other adverse conditions seriously affect the welding quality and the final performance of the product.

[0003] The traditional solution is to use a complex and time-consuming heat treatment method. Specifically, the welded part needs to be preheated at a high temperature of 240-260 DEG C. This step has consumed a lot of energy and time cost. Not only that, but also after welding, the welded part needs to be kept at a high temperature of 420 DEG C for 4 hours, and then slowly cooled. This series of cumbersome operations, although to some extent, can avoid the occurrence of weld cracking and other problems, but inevitably leads to a significant reduction in production efficiency. The original efficient welding production line, because of these additional heat treatment procedures, has to slow down the production rhythm, and the output per unit time has decreased significantly. At the same time, the large consumption of energy, the increase of labor cost and the long time occupation of equipment, all make the production cost rise sharply, which brings heavy burden to the production and operation of enterprises, and also limits the application range and popularization degree of wear-resistant materials in some cost control strict projects. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a welding method of low alloy wear-resistant material with carbon equivalent less than or equal to 1.1, which includes grinding requirements, preheating temperature, welding method, welding parameters, post-welding heat preservation requirements, etc.

[0005] The method provided by the present application comprises the following steps:

[0006] Step 1: remove impurities and oxide skin on the surface of the wear-resistant material;

[0007] Step 2: preheat the base material before welding, use gas shielded welding with protective gas, and the welding material is S307Si, the welding current is 210-280 A, and the welding voltage is 22-31 V;

[0008] Step 3: cover the heat preservation blanket after welding.

[0009] Preferably, the base material is preheated to 160-180 DEG C before welding.

[0010] Preferably, the preheating temperature is 170℃.

[0011] Preferably, the protective gas is 80% Ar + 20% CO2. The gas flow is 15-20 L / min.

[0012] Preferably, the post-weld holding time is 12 hours.

[0013] Preferably, the welding current is 250 A.

[0014] Preferably, the welding voltage is 27 V.

[0015] Preferably, the wire feeding speed is 8 m / min.

[0016] The method of the present application can be applied to the welding of low-alloy wear-resistant materials with a carbon equivalent of 1.1 or less.

[0017] The beneficial effects of the present application are: the present application has made a major breakthrough in solving the key problems faced by wear-resistant material dissimilar steel welding, successfully solved the long-standing industry's welding cracking and parent material delayed cracking and other difficult problems, fundamentally guaranteed the structural integrity and stability of the welded part, greatly improved the reliability and durability of the welding quality, effectively avoided the safety hazards and equipment failures caused by welding defects, and provided a solid quality guarantee foundation for related industrial production. From the perspective of operation implementation and production efficiency, the present application shows incomparable advantages. Its implementation process is simple and easy to operate, without complex operation process and professional skill requirement, which reduces the technical threshold for operators, so that it can be quickly started and efficiently executed in actual production process, and effectively promotes the improvement of production efficiency. Especially in terms of welding efficiency, compared with the traditional wear-resistant material welding method, the present application uses gas shielded welding technology, which greatly improves the welding speed, thereby significantly reducing the time cost of the welding link in the overall production process. Moreover, more outstandingly, the present application completely gets rid of the cumbersome and time-consuming process of post-weld heat treatment, not only simplifies the whole production process, but also greatly reduces the energy consumption and equipment investment in the production process, so that the production cost is effectively controlled and reduced, which creates higher economic benefits and market competitiveness for enterprises, and effectively promotes the wide application and sustainable development of wear-resistant material welding technology in industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 is the metallographic contrast diagram of the grain in the embodiment of the present application; wherein, A is the grain of Example 1, B is the grain of Example 2, C is the grain of Example 3, and D is the grain of Example 4.

[0020] Figures 2-4 is the performance detection diagram of Example 5 of the present application.

[0021] Figure 5 、 Figure 6 is the final product diagram of Example 5 of the present application.

[0022] Figure 7 、 Figure 8 、 Figure 9 is the product cracking schematic diagram in the comparative example of the present application.

[0023] Figure 10 is the welding seam section view of the pilot plate in the present application. DETAILED DESCRIPTION

[0024] The application will be further described in conjunction with the following specific examples and drawings. The process, conditions, experimental methods, etc. for implementing the present application are the general knowledge and common sense in the art, and the present application has no special limitation.

[0025] The purpose of the present application is to provide a welding method for carbon equivalent 1.1 wear-resistant material, which has the characteristics of high welding strength, impact resistance, no welding seam cracking and base material delayed cracking, simple implementation, high welding efficiency, etc.

[0026] The technical solution adopted by the present application is: preheating wear-resistant material dissimilar steel welding, including polishing requirements, preheating temperature, welding method, welding parameters, post-welding heat preservation requirements; the surface impurities of the wear-resistant material are removed by an angle grinder to expose the metal luster. The base material is preheated to 170-180℃ before welding. The protective gas 80% Ar+20% CO2 gas is used for welding, the gas flow is 15-20 L / min, the welding material is S307Si, the welding current is 210-280 A, the welding voltage is 22-31 V. The wire feeding speed is 8 m / min. The post-welding heat preservation blanket is covered for 12 hours.

[0027] Examples 1-4

[0028] The different parameters in Examples 1-4 are shown in Table 1:

[0029] Table 1

[0030]

[0031] The influence of the adjustment of different parameters in Examples 1-4 on the final material performance is shown in Table 2:

[0032] Table 2

[0033] Examples Yield strength Tensile strength Hardness (HRC) Impact 1 1324 MP 1329 MP 28.5～45 26 J to 65 J 2 1405 MP 1411 MP 32.5～46 25～53.5J 3 1134 MP 1184 MP 30～44 25 J to 67 J 4 1243 MP 1248 MP 31.5～47 25 J to 59.5 J

[0034] The yield strength, tensile strength and hardness of the heat-affected zone in the method of Example 2 are superior to those of Example 1; the yield strength, tensile strength and hardness of the post-weld heat-affected zone in Example 2 are superior to those of Example 4.

[0035] As shown in Figure 1 , the metallographic contrast shows that the grains of Example 1 are larger than those of Example 2, and the grains of Example 4 are also larger than those of Example 2; the welding method test shows that the welding performance is best when using a current of 210A-280A and 80% Ar+20% CO2 protective gas.

[0036] Example 5

[0037] The present application is used for welding HARDOX500 wear-resistant steel plate and Q235B of the composite lining plate of the applicant, and the welding performance is excellent, and no cracking failure problem occurs during the use of the product.

[0038] Chemical composition of wear-resistant material

[0039]

[0040] The welding parameters in the present example are: preheating at 170℃, using protective gas 80% Ar+20% CO2 gas for welding, welding material: S307Si, welding current: 250A, welding voltage: 27V, post-welding holding and slow cooling.

[0041] Performance detection is shown in Figures 2-4 : the hardness, impact and tensile strength of the wear-resistant steel plate after welding meet the use requirements.

[0042] The example photos are shown in Figure 5 , Figure 6 .

[0043] Comparative Example 1

[0044] Mechanical properties of wear-resistant material

[0045]

[0046] When the existing method is used to weld the wear-resistant steel, the fracture occurs when the use reaches half of the expected service life, and the number of fractures increases over time, and the proportion of plate fracture is 1.78%, as shown in Figures 7-9 , the red arrow shows that the welding seam crack extends from the welding area and cracks. When the wear-resistant steel plate is welded by the welding method of the present application, no fracture problem occurs in the wear-resistant plate so far.

[0047] The prior art method adopts the process that the base material is preheated by a gun to above 100 DEG C before welding, and the welding is performed by using protective gas of 80% Ar+20% CO2, welding material is ER50-6, welding current is 260A-290A, welding voltage is 27V-30V, and the post-welding heat preservation blanket is covered for 12 hours.

[0048] The protection scope of the present application is not limited to the above-mentioned embodiments. Any changes and advantages conceived by those skilled in the art without departing from the spirit and scope of the present application are included in the present application, and are protected by the appended claims.

Claims

1. A welding method for low alloy wear-resistant materials with a carbon equivalent of less than or equal to 1.1, characterized in that: The following steps are involved: Step 1: Remove impurities and oxide scale from the surface of wear-resistant materials; Step 2: Preheat the base material before welding, use shielded gas welding, welding material: S307Si, welding current: 210A-280A, welding voltage: 22V-31V; Step 3: Cover the insulation with insulation blanket after welding.

2. The welding method according to claim 1, wherein: Preheat the base material to 160℃-180℃ before welding.

3. The welding method according to claim 2, wherein: The preheating temperature is 170°C.

4. The welding method according to claim 1, wherein: The protective gas is 80% Ar + 20% CO2.

5. The welding method according to claim 1, wherein: Keep warm for 12 hours after welding.

6. The welding method according to claim 1, wherein: The welding current is 250A.

7. The welding method according to claim 1, wherein: The welding voltage is 27V.

8. The welding method according to claim 1, wherein: The protective gas flow rate is 15-20L / min.

9. The welding method according to claim 1, wherein: The wire feeding speed is 8m / min.

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