1. Scope of the Standard
This technical regulation establishes comprehensive requirements for seamless stainless steel pipes intended for the transport of liquid media. The document covers classification, coding systems, ordering procedures, geometric parameters (dimensions and tolerances), surface condition requirements, mass, physical and mechanical properties, laboratory testing methods, acceptance rules, as well as standards for marking, packaging, and quality documentation for products supplied by EV Group China.
2. Normative References
Application of this standard requires compliance with the provisions of the following normative documents. In the absence of an issue date, the latest edition of the document, including all amendments, is applicable:
- GB/T 222: Permissible deviations in the chemical composition of steel products.
- GB/T 223.9–223.69: Chemical analysis methods for ferrous metals and alloys to determine the content of Al, Cr, Ti, Cu, Ni, Mo, N, Si, P, Mn, S, C.
- GB/T 228.1: Tensile testing of metallic materials at room temperature.
- GB/T 241: Hydrostatic testing of steel pipes under pressure.
- GB/T 242/246: Flaring and flattening tests.
- GB/T 2102: Acceptance, marking, and certification rules for pipe products.
- GB/T 2975: Preparation of samples for mechanical testing.
- GB/T 4334-2008: Intergranular corrosion resistance testing.
- GB/T 5777-2008 / 7735-2004: Ultrasonic and eddy current non-destructive testing methods.
- GB/T 17395: Dimensions, shapes, and tolerances of seamless steel pipes.
- GB/T 20878: Steel grades, their designation, and chemical composition.
3. Classification and Nomenclature
3.1 Depending on the production technology, pipes from EV Group China are classified as:
- W-H: Hot-deformed (extruded, rolled);
- W-C: Cold-deformed (drawn, cold-rolled).
3.2 According to the accuracy of geometric parameters:
- PA: Standard accuracy;
- PC: High accuracy.
3.3 Symbols: D — outside diameter, S — nominal wall thickness, Smin — minimum wall thickness.
4. Ordering Parameters
When placing a specification with EV Group China, it is necessary to indicate: the standard (number), item name, steel grade, size (D x S), total supply volume (tonnage or length), delivery terms, and any additional requirements (special tests, certification).
5. Geometry, Appearance, and Mass
5.1.1 Supply is carried out based on nominal diameter and wall thickness. Upon agreement, supply based on minimum wall thickness is possible.
| Hot-deformed (W-H) | Cold-deformed (W-C) | |||||||
|---|---|---|---|---|---|---|---|---|
| Parameter | Size | PA | PC | Parameter | Size | PA | PC | |
| D | 68–159 | ±1.25%D | ±1%D | D | 6–10 | ±0.20 | ±0.15 | |
| >159 | ±1.5%D | ±1%D | >10–30 | ±0.30 | ±0.20 | |||
| – | – | – | >30–50 | ±0.4 | ±0.30 | |||
| – | – | – | >50–219 | ±0.85%D | ±1.15%D | |||
| – | – | – | >219 | ±0.9%D | ±0.8 | |||
5.2 Length Requirements
For hot-deformed pipes, the range is 2000–12000 mm; for cold-deformed pipes, it is 1000–12000 mm. Upon customer request, EV Group China supplies pipes of fixed or multiple lengths with cutting allowances (5-15 mm depending on the diameter).
| Deviation Class | Length Tolerance (mm) |
|---|---|
| L1 | 0–20 |
| L2 | 0–10 |
| L3 | 0–5 |