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Professional special operations stainless steel belt welding precautions

Professional special operations stainless steel belt welding precautions

Time:2022-04-02 Source:Wuxi Jianuo Special Steel Co., Ltd.

Special operations stainless steel belt welding and welding material selection are based on experiments, to test data shall prevail, so it is often necessary to conduct the necessary process tests and performance tests. To meet the requirements of use.

First, to ensure that the weld metal has a certain degree of denseness, there should not be over the standard welding defects.

Second, to ensure that the weld head has good process performance, that is, in the joint area can not appear hot and cold cracks.

Third, to ensure that the weld metal has the required comprehensive performance, such as corrosion resistance, heat resistance, thermal strength, oxidation resistance, etc.

Fourth, in the welding process (such as preheating before welding or post-weld heat treatment) is limited, pay attention to the choice of nickel-based alloy or austenitic stainless steel welding materials to improve the plasticity and toughness of the weld metal.

Fifth, when welding dissimilar materials, the choice of welding materials is usually on the high not on the low. Such as low-alloy steel and stainless steel welding, the choice of stainless steel welding materials; low-alloy steel and nickel-based alloy welding or stainless steel and nickel-based alloy welding, the choice of nickel-based alloy welding materials.

Sixth, to ensure the use of welded joints, that is, to ensure that the weld metal transition zone, heat-affected zone and other joint areas have good performance to meet the requirements of use.

Such as low-alloy heat-resistant steel and 1Cr18Ni9Ti welding, in many cases, the use of 309 type austenitic stainless steel welding materials can meet the requirements. When the design requirements of the joint has good hot and cold fatigue performance, if also using 309 type austenitic stainless steel welding materials, although the formation of a complete welded joint, but due to the austenitic weld and low alloy heat-resistant steel thermal expansion coefficient difference between the two sides of the fusion zone produces a large thermal stress, with the change of hot and cold, thermal stress also constantly alternating changes, coupled with low carbon or low alloy steel side of the plasticity is low, which reduces the cold and hot fatigue performance of the joint.

If the choice of nickel-based alloy welding materials, can greatly improve the cold and heat fatigue performance of the joint. This is mainly due to the coefficient of thermal expansion of nickel-based alloys between the two welded materials, and closer to low-carbon or low-alloy steel, so that the thermal stress is dispersed, and less plasticity of low-carbon or low-alloy steel side of the stress is relatively small.