Performance Details of Q690D Seamless Steel Pipe

Q690D seamless steel pipe implements the standard GB/T8162 seamless steel pipe for structure
Outer diameter: 10mm~762mm, wall thickness 3mm~150mm.
Production method: hot rolling, cold drawing, delivery status: heat treatment.
Chemical composition: Carbon: ≤0.18, Silicon: ≤0.60, Manganese: ≤2.0, Phosphorus: ≤0.025, Sulfur: ≤0.015, Niobium: ≤0.11, Vanadium: ≤0.20, Titanium: ≤0.20, Chromium: ≤1.0, Nickel: ≤0.08, Copper: ≤0.20, Nitrogen: ≤0.015, Molybdenum: ≤0.30, Boron: ≤0.005, Aluminum: ≥0.015
Mechanical properties: Tensile strength: 770~940MPa, Wall thickness ≤16 lower yields≥690, 16mm~30mm wall thickness yield ≥660MPa, ≥30 wall thickness yield ≥620, elongation after fracture: ≥14, -20 degree impact, ≥47.

Bending of Q690D seamless steel pipe
According to the requirements of the buyer, after negotiation between the supply and demand parties and indicated in the contract, steel pipes with an outer diameter not exceeding 22mm can be subjected to bending tests, with a bending angle of 90° and a bending core radius of 6 times the outer diameter of the steel pipe. After bending, no cracks or cracks should appear at the bending of the specimen.

Surface quality of Q690D seamless steel pipe
There should be no visible cracks, folds, scars, roll folds, or delamination on the inner and outer surfaces of the steel pipe. These defects should be completely removed, the removal depth should not exceed the lower deviation of the nominal wall thickness, and the actual wall thickness at the cleaning location should not be less than the minimum value allowed by the wall thickness. Other local defects that do not exceed the lower deviation of the wall thickness are allowed to exist.

Nondestructive testing of Q690D seamless steel pipe
According to the requirements of the buyer, after negotiation between the supply and demand parties and indicated in the contract, the steel pipe can be nondestructively tested by one or more of the following methods:
a) When ultrasonic testing is carried out in accordance with the provisions of GB/T 5777-2008, the groove depth level of the comparison sample pipe is: L3 for cold-drawn (rolled) pipes and L4 for hot-rolled (expanded) steel pipes;
b) Eddy’s current testing is carried out in accordance with the provisions of GB/T 7735-2016, and the acceptance level is E4H or E4;
c) Magnetic leakage testing is carried out in accordance with the provisions of GB/T 12606-2016, and the acceptance level is F4.