Method for improving welding deformation of high-strength alloy steel

Abstract

The invention belongs to the field of steel welding, and discloses a method for improving welding deformation of high-strength alloy steel. When austenite in the high-strength alloy steel is converted into martensite, along with volume expansion, different martensite transformation temperatures and different volume expansion amounts of the martensite are different, and finally different welding deformation degrees are caused. A proper amount of Sn element powder is added into deposited metal powder, the martensite transformation temperature of the deposited metal powder can be effectively changed, welding deformation is reduced by adjusting the martensite transformation temperature, and the welding deformation degree of the high-strength alloy steel can be greatly controlled.

Description

Technical Field

[0001] The invention belongs to the field of steel welding and relates to a method for improving welding deformation of high-strength alloy steel. Background Art

[0002] During the welding process, welding deformation is one of the inevitable and most difficult problems to solve for high-strength alloy steel (strength greater than 1300MPa). Welding deformation is mainly caused by the solidification shrinkage caused by uneven heating and cooling of the welding thermal cycle. Although scholars from various countries have done a lot of work on improving welding deformation, the methods used for different materials are different due to the limitations of the material's own characteristics and the working environment. At present, the methods to improve the welding deformation of high-strength alloy steel mainly include changing the welding process, anti-deformation method and rigid fixation method.

[0003] Specific materials have their own fixed welding processes, and it is often difficult to achieve the desired goal by changing the welding process within its range. Although the reverse deformation method is very effective, it is difficult to accurately predict the deformation direction and size before welding. Although the rigid fixation method is simple and flexible, there is a certain degree of rebound after the rigid constraint is removed. Although there are many methods to control welding deformation, they all have their limitations. Due to the different martensitic transformation temperatures of high-strength alloy steels, their volume expansion will be different, resulting in different welding deformation sizes. Therefore, it is very important to design the martensitic transformation temperature corresponding to the minimum welding deformation. There is no doubt that the martensitic transformation temperature of high-strength alloy steel can be changed by reasonably changing the composition of the deposited metal. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for improving the welding deformation of high-strength alloy steel. Under the premise of not reducing its mechanical properties, the martensitic transformation temperature of the high-strength alloy steel is adjusted by adding a trace amount of Sn element to obtain the Sn content corresponding to the minimum deformation, thereby achieving the purpose of improving the welding deformation of the high-strength alloy steel.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for improving welding deformation of high-strength alloy steel, wherein the filler metal raw materials are all fine powders, and the particle size range of each fine powder is 53-105 μm. The filler metal raw materials include iron powder, carbon powder, Cr powder, Ni powder, Mn powder, Mo powder, and Sn powder; the main raw material physical and chemical performance indicators are Fe mass percentage content in iron powder>99%, C content in carbon powder>97%, Cr content in Cr powder>99%, Ni content in Ni powder>99%, Mn content in Mn powder>99%, Mo content in Mo powder>99% and Sn content in Sn powder>99%.

[0007] A method for improving welding deformation of high-strength alloy steel, the main production method is as follows:

[0008] (1) Determine the formula;

[0009] The components and contents of the filler metal raw material formula are: C powder: 0-0.1%, Cr powder: 10-30%, Ni powder: 0-20%, Mn powder: 5-10%, Mo powder: 0-1% and Sn powder: 0-0.5%, and the rest is Fe powder, calculated by mass percentage.

[0010] (2) Weigh C, Cr, Ni, Mn, Mo, Sn and Fe powders according to the formula ratio and set aside.

[0011] (3) Put the weighed powders into the mixer and mix for 30 to 50 minutes. After mixing evenly, randomly take a certain amount of the mixed material for chemical composition testing. The difference between the test and the formula is accurate to two decimal places. If it exceeds two decimal places, re-mix until it is accurate to two decimal places.

[0012] (4) Put the mixed powder into the silo and set aside.

[0013] (5) Two high-strength alloy steel plates were made by wire cutting. The plate size was 200×100×5 mm, the groove was 45°, and the blunt edge was 1 mm. The plate profile shape and size were as follows: Figure 1 As shown:

[0014] (6) At room temperature, two high-strength alloy steel plates are butt-welded using fiber laser automatic welding. The mixed powder is sent to the weld, and the powder beam and the light beam intersect at one point. Powder is sent while welding. The welding process is: the powder feeding speed is 0.54~1.50cm 3 / min, laser welding power is 3~5kW, welding speed is 150mm / min, defocusing amount is -4~+4mm, shielding gas flow rate is 5~25L / min (Ar and CO2 mixed gas). There is no incomplete penetration after welding.

[0015] (7) After the two steel plates are butt-jointed, place them at room temperature for 12 to 24 hours.

[0016] According to GB / T11337-2004, the flatness is measured by the cross straight line criterion and the obtained data is recorded.

[0017] When austenite in high-strength alloy steel transforms into martensite, it is accompanied by volume expansion. Different martensite transformation temperatures result in different volume expansions, which ultimately lead to different degrees of welding deformation. Adding an appropriate amount of Sn element powder to the deposited metal powder can effectively change its martensite transformation temperature. By adjusting the martensite transformation temperature, the welding deformation can be reduced, which can greatly control the welding deformation degree of high-strength alloy steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a high-strength alloy steel welded plate specimen. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0020] The present invention provides a method for improving welding deformation of high-strength alloy steel, and the specific process is as follows:

[0021] (1) According to the following formula, three groups of Sn fine powder and Sn-free fine powder were made for comparative test. The specific formula is as follows:

[0022]

[0023] (2) Weigh C, Cr, Ni, Mn, Mo, Sn and Fe powders according to the formula ratio and set aside.

[0024] (3) Put the weighed elements into the mixer and mix them for 30 to 50 minutes. After mixing evenly, randomly take a certain amount of the mixed material for chemical composition testing. The difference between the test and the formula is accurate to two decimal places. If it exceeds two decimal places, re-mix until it is accurate to two decimal places.

[0025] (4) Put the mixed material into the silo for later use.

[0026] (5) Two high-strength alloy steel plates were made by wire cutting. The plate size was 200×100×5 mm, the groove was 45°, and the blunt edge was 1 mm. The plate profile shape and size are as shown in the following figure:

[0027] (6) At room temperature, two high-strength alloy steel plates are butt-welded using fiber laser automatic welding. Fine powder is delivered to the weld, and the powder beam and light beam intersect at one point, while welding is performed. The welding process is: the powder delivery speed is 0.54 to 1.50 cm 3 / min, laser welding power is 3-5kW, welding speed is 150mm / min, defocusing amount is -4-+4mm, shielding gas flow is 5-25L / min, shielding gas is Ar and CO2 mixed gas. There is no incomplete penetration after welding.

[0028] (7) After the two steel plates are butt-jointed and welded, place them at room temperature for 12 to 24 hours.

[0029] The present invention designs a method for improving the cold crack resistance of high-strength alloy steel in welding. Three groups of mixed metal powders containing Sn and those without Sn are not subjected to deposition tests. According to GB / T11337-2004, the flatness is measured by the cross line criterion, and the obtained data is recorded. The results show that the flatness of the three groups of high-strength alloy steels containing Sn in welding deformation is 1.8, 2.0 and 1.7 cm, while the flatness of the three groups of high-strength alloy steels without Sn is 6.4, 7.2 and 6.7 cm. This shows that the addition of Sn element can effectively improve the degree of welding deformation of high-strength alloy steel.

Claims

1. A method for improving welding deformation of high-strength alloy steel, characterized in that: The following steps are involved: (1) Determine the formula; The components and contents of the filler metal raw material formula are as follows: C powder: 0-0.1%, Cr powder: 10-30%, Ni powder: 0-20%, Mn powder: 5-10%, Mo powder: 0-1% and Sn powder: 0-0.5%, and the rest is Fe powder, calculated by mass percentage; (2) Weigh C, Cr, Ni, Mn, Mo, Sn and Fe powders according to the formula ratio and set aside; (3) The weighed powders are placed in a mixer for mixing. After mixing evenly, a certain amount of the mixed material is randomly taken for chemical composition testing. The difference between the test and the formula is accurate to two decimal places; If it exceeds two decimal places, remix until it is accurate to two decimal places; (4) Put the mixed powder into the silo for later use; (5) Two high-strength alloy steel plates were made by wire cutting with a groove angle of 45°; (6) At room temperature, two high-strength alloy steel plates are butt-welded using fiber laser automatic welding. The mixed powder is sent to the weld, and the powder beam and the light beam intersect at one point. Powder is sent while welding, and there is no incomplete penetration after welding; (7) After the two steel plates are butt-jointed and welded, place them at room temperature for 12 to 24 hours.

2. A method for improving welding deformation of high-strength alloy steel as claimed in claim 1, characterized in that: In step (1), the mass percentage of Fe in the iron powder is greater than 99%, the mass percentage of C in the carbon powder is greater than 97%, the mass percentage of Cr in the Cr powder is greater than 99%, the mass percentage of Ni in the Ni powder is greater than 99%, the mass percentage of Mn in the Mn powder is greater than 99%, the mass percentage of Mo in the Mo powder is greater than 99%, and the mass percentage of Sn in the Sn powder is greater than 99%.

3. A method for improving welding deformation of high-strength alloy steel as claimed in claim 2, characterized in that: In step (1), the particle size of each fine powder ranges from 53 to 105 μm.

4. A method for improving welding deformation of high-strength alloy steel as claimed in claim 1, characterized in that: In step (3), the mixing is carried out for 30 to 50 minutes.

5. A method for improving welding deformation of high-strength alloy steel as claimed in claim 4, characterized in that: In step (5), the plate size is 200×100×5 mm.

6. A method for improving welding deformation of high-strength alloy steel as claimed in claim 5, characterized in that: The blunt edge of the plate is 1 mm.

7. A method for improving welding deformation of high-strength alloy steel as claimed in claim 6, characterized in that: In step (6), the welding process parameters are as follows: the powder feeding speed is 0.54 to 1.50 cm 3 / min, laser welding power is 3~5kW, welding speed is 150mm / min, defocusing amount is -4~+4mm, and shielding gas flow rate is 5~25L / min.

8. A method for improving welding deformation of high-strength alloy steel as claimed in claim 7, characterized in that: The protective gas is a mixture of Ar and CO2.

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