Issues with steel section materials in stainless steel equipment
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For stainless steel equipment, when angle steel or channel steel is required, such as for the angle steel columns of the flat covers on the tops of stainless steel tanks, in the past we would weld stainless steel gaskets to our equipment first and then weld Q235B angle steel onto them. Recently, it was found that a certain engineering company directly welded Q235 angle steel to stainless steel equipment, which reduced the amount of work required for prefabricating and welding stainless steel gaskets significantly. What do people think of this approach? Furthermore, when an external reinforcement ring needs to be installed for externally pressurized equipment, if a stainless steel gasket is welded to the equipment first and then Q235B angle steel is welded, it is necessary to recalculate the combined moment of inertia and enter these values into the software; this adds extra work to the calculation process and reduces its efficiency. Can Q235 angle steel be directly welded to stainless steel equipment? What are people’s opinions on this approach?
Reinforcing ribs on the outside of the container, made of carbon steel materials such as angle steel or I-beam, can be welded directly to the container without any problem, as long as the external operating conditions permit it. Adding stainless steel shims not only increases the welding workload but also poses significant challenges to controlling welding deformation in stainless steel; it is unnecessary unless environmental requirements dictate it.
Such a structure exists on the outside of the device.
I agree with you; my company does the same thing – it’s pointless to use stainless steel shims externally.
I think it’s not allowed; contact between stainless steel and carbon steel causes corrosion, so spacers should be used to separate them.
Isn’t it all for the sake of saving time and reducing costs?·····
The gasket flange is in contact with both carbon steel and stainless steel, and it is also located inside the medium.
In general, the external reinforcement structures of stainless steel containers are made of carbon steel, mainly due to cost considerations; this approach is acceptable as long as the operating conditions permit it.
Of course, when using carbon steel reinforcement, attention must be paid to the pickling and passivation of the outer surface of the container, as well as to the corrosion protection of the carbon steel. Both the welding of dissimilar steels and the types of welded structures need to be taken into consideration.