ERW Pipe Technical Requirements

• Yield strength of the N80 is higher than the J55 up to 173 ~ 206 MPa.
• On the same area of ??the sample, the elongation of N80 is higher than J55.
• Under the same size, the same sample orientation, the same minimum sample size, J55 grade couplings, coupling stock, coupling material, semi-finished and coupling attachment material can absorb lower than N80 steel grade.
• The nondestructive testing methods of seamless pipe,coupling stock, welded tube with J55 and N80 is differeent.
• J55 and N80 steel grade is not the same color: length greater than or equal 1.8m, J55 painted a bright green, N80 painted a red;
• J55 chosen by the manufacturer, or organize according to the order specified length normalized (N), normalizing and tempering (N & T) or quenching and tempering (Q & T). N80 is a whole, full-length heat treatment is mandatory. By the manufacturer selected for normalizing (N) or normalizing and tempering (N & T) + quenching (Q).