Issues regarding the material of GB/T 12459 steel butt-welded seamless pipe fittings
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We will focus solely on carbon steel. Are steel butt-welded seamless pipe fittings, such as elbows and tees, manufactured from seamless pipes? If they are produced in accordance with the GB8163 standard, are there elbows and tees made of material Q235? (GB8163 does not have the Q235 material.) 2. How are pipe caps generally manufactured? Are they made by stamping steel plates? What is the general material? Q235 or steel grade 20?
The pipe caps are forged; they should not be made of Q235 steel, but rather of 20#, 10#, manganese steel, or stainless steel. The large pipe fittings are welded together, but they must pass flaw detection tests in accordance with the GBT13401 standard
The forum has relevant standards; the original poster should download and take a look
I have the relevant paper standards; in accordance with GB12459, Q235 material can be used for manufacturing. It is practically impossible to use steel plates for making elbows, tees, etc. If the pipe caps are also forged, then there should be no seamless pipe fittings made of Q235 material
GB/T12459 is the domestic standard for seamless pipe fittings; according to this standard, the fittings must be seamless. Q235 is not listed in GB8163, but if the customer insists on using Q235, there must be a material in GB8163 whose chemical and mechanical properties are very similar to those of Q235; that’s why the customer asks you to use Q235. Those with a gland pressure of less than 160 S are usually manufactured by cold pressing or hot pressing of steel plates, while those with a pressure of 160 S or higher generally use forgings. The cost of hot pressing is higher than that of cold pressing, while the cost of forgings is higher than that of hot pressing. The materials include stainless steel (304, 316, 321, duplex steel, etc.), alloy steel (16Mn, etc.), and carbon steel (20#, Q235, etc.). See what materials are needed for the engineering project. Some materials are also prone to cracking (such as carbon steel, duplex steel, etc.), and hot pressing can be used for them; if hot pressing doesn’t work, then forging is the only option.