A53 United States standard seamless steel pipe corresponding to the domestic material ? answer: 20 # carbon steel seamless pipe
First, 20 # seamless steel pipe product profile
20 # seamless steel pipe with its excellent performance and suitable price is widely used in petrochemical and other industries. 20 # GB / T8163-2008 "seamless steel pipe for fluid transmission", GB3087-2008 "seamless steel pipe for low and medium pressure boilers", GB9948-2013 "Seamless steel pipe for petroleum cracking" and GB6479-2013 "High-pressure fertilizer equipment Seamless steel pipe "and other national standards.
Different standards of 20 # seamless steel pipe in the price and the use of performance there is a big difference. Currently on the market 20 # seamless steel pipe manufactured according to GB 6479-2013 than GB / T 8163-2008 manufacturing price of about 1,000 yuan / ton.
20 # seamless steel pipe are what standards?
① GB / T 8163-2008 seamless steel pipe for fluid transportation
② GB 3087-2008 low and medium pressure boiler seamless steel pipe
③ GB 9948-2013 petroleum cracking seamless steel pipe
④ GB 6479-2013 high-pressure fertilizer equipment seamless steel pipe
⑤ GB 5310-2008 high-pressure boiler seamless steel pipe (the standard steel No. 20G; G said the boiler pipe)
Second, 20 # chemical composition
As can be seen from Table 1: The main elements (such as C, Si, Mn) of the chemical composition of 20 # seamless steel pipe in each material standard are all the same. The content of residual elements (such as Ni, Cr, Cu, Mo, V) in steel GB 9948-2013 and GB 6479-2013 are the same, but GB / T 8163-2008 is slightly different from the above two standards, the main chemical composition The difference lies in the P, S content.
Third, 20 # mechanical properties (mechanical properties)
It can be seen from Table 2 that the tensile strength of 20 # seamless steel pipe in each material standard is basically the same, the main difference is the impact test.
According to GB / T8163-2008 20 # seamless steel pipe manufacturing, no impact test inspection, only when the demand side, after consultation between the supply and demand, and in the contract specified impact test before the Charpy V-notch impact test.
According to GB 9948-2013 20 # seamless steel pipe, only for the outer diameter of not less than 76mm and the wall thickness of not less than 14mm at room temperature impact test, the impact of other specifications of the steel pipe to be tested by the supply and demand sides negotiated and in the contract Agreement.
According to GB 6479-2013 20 # seamless steel pipe, D ≥ 76mm and S ≥ 6.5mm steel pipe provided 0 ℃ impact test.
Obviously, according to GB 6479-2013 20 # seamless steel pipe, the mechanical properties of the requirements of the other two standards higher.
Fourth, 20 # material substitution problem
In the procurement phase or on-site construction process, construction units often propose to the design agency material substitution problems. In addition to the pipeline specifications require substitution, when using other standard production of steel instead, the designer should pay attention to the design conditions and standard differences in order to correctly sign a single confirmation.
a) 20 # seamless steel pipes produced according to GB 6479-2013 and GB 9948-2013 can replace 20 # seamless steel pipes produced according to GB 3087-2008 and GB / T 8163-2008 under the same specifications .
b) Since 20 # seamless steel pipes produced according to GB 6479-2013 and GB 9948-2013 have excellent toughness, it is recommended that steel pipes used under low temperature of not lower than -20 ° C be made according to GB 6479-2013 and GB 9948-2013 standard production of 20 # seamless steel pipe.
c) According to GB / T 8163-2008 standard production of 20 # seamless steel pipe only for general fluids. As GB 3087-2008 standard GB / T 8163-2008 standard wall thickness tolerances, bending test, low magnification test and surface quality requirements higher, while GB 3087-2008 standard also provides high temperature strength requirements, therefore Under the condition that the maximum test pressure is not more than 10MPa, 20 # seamless steel pipe produced according to GB 3087-2008 standard can replace 20 # seamless steel pipe produced according to GB / T 8163-2008 standard. When the pipe wall thickness ≥ 15mm, replacement should pay attention to calculate the wall thickness of steel.