Tests on stainless steel welding and intergranular corrosion
Thread Content
I recently saw a drawing of a heat exchanger, whose heat exchange tubes are made of 0Cr18Ni9 material, which meets the requirements specified in \"GB 13296-2007 Stainless Steel Seamless Tubes for Boilers and Heat Exchangers\". One of the technical requirements states that specimens of stainless steel welded joints after sensitization treatment shall undergo intergranular corrosion testing in accordance with the requirements of GB/T4334.5. As far as I know, many drawings of stainless steel pressure vessels these days do not specify the requirements for intergranular corrosion testing. But since the drawings specify this technical requirement, does the manufacturer need to carry out this test before welding? If it is possible to avoid the sensitization temperature range during welding or to prevent sensitization, can this test then be omitted? I also want to ask, what is the common welding process for ordinary austenitic stainless steel nowadays? For example, inter-layer temperature control, post-weld cooling methods, welding current, voltage, speed for 6mm stainless steel plates, and so on... the more detailed, the better. . . It would be best if it could be closely aligned with actual production practices! ! ! Thank you……
Intergranular corrosion tests should be conducted; there are standards for this. What you need are the technical specifications for stainless steel welding; there are standards for this.
As long as the specification requires intergranular corrosion resistance for stainless steel, this factor should be taken into account during manufacturing and welding. Specifically, when conducting welding procedure qualification, requirements for intergranular corrosion testing should be added. For the products, intergranular corrosion test specimens with welded joints should be provided, including the casing and heat exchange tubes. As required by the pattern, this specimen also needs to undergo sensitization heat treatment first.
I’m not sure about the specific procedures; I only know that a process evaluation is required, involving a crystal corrosion test on the welded joints of the test specimens. This evaluation is then incorporated into the welding process. In reality, it’s not possible to conduct a crystal corrosion test after welding – it can only be done using the test specimens
Preparing samples for intergranular corrosion in stainless steel is no longer a difficult task. Beijing Tiger Ruixiang Technology Co., Ltd. is a company that specializes in manufacturing fully automatic equipment for preparing such samples; this equipment is used to grind samples in accordance with **standards, following the direction of the stainless steel tube necks, the rolling direction of the stainless steel plates, and the weld lines. For more details, please visit the company’s website at www.bjtgrx.com