Relevant provisions in the national standard for pipe fittings “GB/T13401-2017 Technical Specifications for Steel Butt-welded Pipe Fittings”:
First, nondestructive testing
1. Tees, crosses, pressed reducers and pipe caps formed by direct cutting of bars of all material categories shall be nondestructively tested piece by piece; among them, carbon steel, alloy steel and low-temperature steel categories shall be subjected to magnetic particle testing according to NB/T47013.4 or relevant specifications, and stainless steel categories shall be subjected to penetration testing according to NB/T47013.5 or relevant specifications, and level I is qualified.
2. In addition to the varieties mentioned in 1, other pipe fittings of the alloy steel category (including pipe fittings of material grades LF450K3 and LF680K4 in the low-temperature steel category) shall be magnetically tested piece by piece according to NB/T47013.4 or relevant specifications, and level I is qualified.
3. In addition to provision 5, when the welds of welded pipe fittings are completed by the pipe fitting manufacturer, the full length of the welds of the welded pipe fittings shall be radiographically inspected according to NB/T47013.2 or relevant specifications, and Level II shall be qualified (excluding the flanged short section manufactured according to 5.6).
4. In addition to provision 5, for welded pipe fittings made of straight seam welded pipes, if the welds have been 100% radiographically inspected by the welded pipe manufacturer and Level II is qualified, the welds of the pipe fittings may no longer be radiographically inspected unless otherwise required. If the welds of the welded pipe have not been 100% radiographically inspected by the welded pipe manufacturer, the full length of the welds of the welded pipe fittings shall be radiographically inspected according to NB/T47013.2 or relevant specifications, and Level II shall be qualified.
5. For welded pipe fittings whose use conditions do not require weld radiographic inspection, the welds may not be radiographically inspected after negotiation between the supply and demand parties, but the suffix letter NX shall be added after the pipe material grade in the delivery documents and physical marks, such as CF370NX.
6. In addition to the above provisions, non-destructive testing can be carried out according to the content negotiated by the supply and demand parties; such as magnetic powder, penetration, and ultrasonic testing as required.
Second, the relevant provisions of the national standard for flanges “GB/T9124-2010 Technical Conditions for Steel Pipe Flanges”:
1. Low carbon steel and austenitic stainless steel forgings for flanges with a nominal pressure of PN2.5-PN16 Class 150 are allowed to use Class I forgings (hardness test piece by piece).
2. Forgings for flanges that meet one of the following conditions, shall meet the requirements of Class III or above forgings (random inspection and stretching and ultrasonic testing piece by piece):
① Forgings for flanges with a nominal pressure of ≥PN100 and ≥Class600;
② Chromium-molybdenum steel forgings for flanges with a nominal pressure of ≥PN63 and ≥Class300;
③ Ferrite forgings for flanges with a nominal pressure of ≥PN25 and greater than or equal to Class≥300 and a working temperature of ≤-20℃.
3. Forgings for other flanges shall meet the requirements of Grade II or above forgings (random inspection and stretching).
Post time: Jan-15-2025