Technical description of the ASTM/ASME A/SA 268 standard
The ASTM A268/ASME SA 268 specification regulates the technical requirements for seamless and welded ferritic and martensitic stainless steel tubing with nominal wall thickness. These products, supplied by EV Group China, are intended for operation in environments with high corrosive aggressiveness and under exposure to high temperatures. The specified steel grades belong to the high-chromium alloy group and possess pronounced ferromagnetic properties.
Among the regulated steel grades, TP410 and UNS S41500 (see the table below) are capable of being hardened during the heat treatment process. It is important to note that high-chromium ferritic alloys are prone to embrittlement when cooled slowly to room temperature, which requires strict adherence to technological regimes during installation and operation.
Special attention should be paid to the TP439 grade, which is optimized for the manufacture of hot water vessels. The advantage of this steel lies in the lack of necessity for additional heat treatment after welding, which eliminates the risk of forming heat-affected zones susceptible to corrosion.
When placing an order with EV Group China, it is possible to agree upon additional product requirements. The standard provides for the use of two independent unit systems: SI and inch-pound. These systems are not direct equivalents and must be used strictly separately to ensure compliance with the specification.
| Steel grade | UNS | Type |
|---|---|---|
| TP410 | S41000 | Martensitic |
| TP439 | S43035 | Ferritic |
| – | S41500 | Martensitic |