CN105689926A - Welding method capable of reducing rack cold cracks - Google Patents

Abstract

The invention discloses a welding method capable of reducing rack cold cracks. The welding method is characterized by comprising the following requirements of (1) pre-welding preheating and post-welding slow cooling; (2) adoption of an alkaline welding rod or a welding flux; (3) welding rods and a welding flux, adoption of the low-hydrogen welding rod, and 1-2 h of heat preservation at the temperature of 300 DEG C-350 DEG C; the acidic welding rod, and 1 h of heat preservation at the temperature of 100 DEG C-150 DEG C; and the welding flux, and 2-2.5 h of heat preservation at the temperature of 200 DEG C-250 DEG C; and (4) conducting of post-welding in-time heat treatment. According to the welding method capable of reducing the rack cold cracks, the process is optimized and more reasonable, and the whole cold cracks can be reduced.

Description

A kind of welding method reducing frame cold crack

Technical field

The invention belongs to welding procedure field, specifically a kind of welding method reducing frame cold crack。

Background technology

After welding machine frame, its structure is usually present cold crack, cold crack refers to that weld seam temperature in cooling procedure drops to less than 300 200 DEG C generations within the scope of martensite transformation temperature, can occur immediately after welding, it is also possible to the long period after welding just occurs, therefore also referred to as delayed crack。The primary condition of its formation has 3: welding point forms hardened structure；The existence of diffusible hydrogen and concentration；There is bigger welding tensile stress。

Summary of the invention

It is an object of the invention to for Shortcomings part in above-mentioned technology, the present invention provides a kind of welding method reducing frame cold crack, and process optimization is more reasonable, it is possible to reduce cold crack。

The technical scheme realizing the object of the invention is as follows:

A kind of welding method reducing frame cold crack, is characterised by, including claimed below:

(1) weld preheating 250-300 DEG C, postheating to 150-200 DEG C；

(2) basic electrode or solder flux are adopted, to reduce the diffusion oxygen content in weld seam；

(3) welding rod and solder flux: adopt low-hydrogen electrode 300 DEG C-350 DEG C, is incubated l-2h；Acidic electrode l00 DEG C～l50 DEG C insulation lh；Solder flux 200～250 DEG C, is incubated 2-2.5h；Groove and welding wire degrease, moisture and rust staining, to reduce the source of hydrogen；

(4) postwelding carries out heat treatment in time: being annealed processing, annealing temperature 500-550 DEG C, time 2-4h, stove is cooled to 300 DEG C of air coolings of coming out of the stove, rate of cooling 20-60 DEG C/h, is heated to 200-350 DEG C, is incubated 2-6 hour。

A kind of welding method reducing frame cold crack of the present invention, its weld preheating, postheating or after heat etc. are to accelerate hydrogen molecule effusion；Degrease, moisture and rust staining foul, to reduce the source of hydrogen；Annealing, to eliminate internal stress, improves its toughness, and process optimization is more reasonable, it is possible to reduce overall cold crack。

Detailed description of the invention

Below in conjunction with embodiment, the invention will be further described:

A kind of welding method reducing frame cold crack, is characterised by, including claimed below:

(1) weld preheating 250-300 DEG C, postheating to 150-200 DEG C；

(2) basic electrode or solder flux are adopted, to reduce the diffusion oxygen content in weld seam；

(3) welding rod and solder flux: adopt low-hydrogen electrode 300 DEG C-350 DEG C, is incubated l-2h；Acidic electrode l00 DEG C～l50 DEG C insulation lh；Solder flux 200～250 DEG C, is incubated 2-2.5h；Groove and welding wire degrease, moisture and rust staining, to reduce the source of hydrogen；

(4) postwelding carries out heat treatment in time: being annealed processing, annealing temperature 500-550 DEG C, time 2-4h, stove is cooled to 300 DEG C of air coolings of coming out of the stove, rate of cooling 20-60 DEG C/h, is heated to 200-350 DEG C, is incubated 2-6 hour。

A kind of welding method reducing frame cold crack of the present invention, its weld preheating, postheating or after heat etc. are to accelerate hydrogen molecule effusion；Degrease, moisture and rust staining foul, to reduce the source of hydrogen；Annealing, to eliminate internal stress, improves its toughness, and process optimization is more reasonable, it is possible to reduce overall cold crack。

The preferred embodiment of the present invention described in detail above。Should be appreciated that those of ordinary skill in the art just can make many modifications and variations according to the design of the present invention without creative work。All technical staff in the art, all should in the protection domain being defined in the patent claims under this invention's idea on the basis of existing technology by the available technical scheme of logical analysis, reasoning, or a limited experiment。

Claims (1)

1. reduce a welding method for frame cold crack, be characterised by, including claimed below:

(1) weld preheating 250-300 DEG C, postheating to 150-200 DEG C；

(2) basic electrode or solder flux are adopted, to reduce the diffusion oxygen content in weld seam；

(3) welding rod and solder flux: adopt low-hydrogen electrode 300 DEG C-350 DEG C, is incubated l-2h；Acidic electrode l00 DEG C～l50 DEG C insulation lh；Solder flux 200～250 DEG C, is incubated 2-2.5h；Groove and welding wire degrease, moisture and rust staining, to reduce the source of hydrogen；

(4) postwelding carries out heat treatment in time: being annealed processing, annealing temperature 500-550 DEG C, time 2-4h, stove is cooled to 300 DEG C of air coolings of coming out of the stove, rate of cooling 20-60 DEG C/h, is heated to 200-350 DEG C, is incubated 2-6 hour。