The difference between 20# flange and Q235B flange; Can these two carbon steel flange materials be used interchangeably? Our seamless steel pipe is 20# steel pipe can be welded with Q235B flange? Regarding these topics, I will give you a brief introduction today.
The steel number of 20# corresponds to two national standards: one is the GB/T8163-2018 seamless steel pipe manufacturing standard for fluid transportation, and the other is NB/T{{2} } carbon steel and alloy steel forgings for pressure support equipment.
The corresponding national standard of Q235B steel number is GB711-2008, GB/T3274-2017 carbon structural steel and low-alloy structural steel hot-rolled steel plate and steel strip, Q235B is generally made of steel plate, there are also welded pipes made of this steel plate such as Q235B GB/T3091-2015 and Q235B SY/T5037-2018 standard steel pipe.
Use temperature: Q235B general use temperature is -10 ~ 350 degree , 20# steel use temperature is -20 ~ 425 degree ;
Use pressure: Q235B generally requires design pressure less than 3.0MPa; 20# steel can withstand higher pressure;
Applicable medium: Q235B is generally used in non-toxic non-combustible pipeline media, but also used in structural steel such as support hangers, etc., Q235B should not be used for liquefied hydrocarbons, the toxicity degree is highly and extremely harmful; 20# steel is most widely used, and 20# steel can be used in toxic, flammable and explosive media.
The chemical composition of 20# and Q235B is very similar and the physical properties are similar, although Q235B and 20# steel are two materials, but they can be welded together, there is no difference in welding. Generally, flanges are made of forgings, forgings are generally 20# material, from the material point of view, 20# if it is pipe or forgings are higher than Q235B.
