ASTM A312 253MA / UNS S30815 / EN 1.4835 Stainless Steel Seamless Pipe

253MA is a heat-resistant austenitic stainless steel alloy. It contains chromium, nickel, and nitrogen as its main alloying elements. This alloy offers excellent oxidation resistance at high temperatures up to 1150°C, making it suitable for use in high-temperature applications such as furnace components, heat exchangers, and exhaust systems. They are commonly used in industries such as chemical processing, power generation, and oil and gas exploration. It is designed to fill the gap between standard 304/316 stainless steels and more expensive high-alloy steels and nickel-based alloys.

Chemical Composition of Stainless Steel Seamless Pipe Pickling

Physical properties of ASTM A312 253MA Stainless Steel Seamless Pipe Pickling

Mechanical Properties of ASTM A312 253MA Stainless Steel Seamless Pipe Pickling

• Process:

​ Pickling involves immersing the stainless steel pipe in a bath of mixed acids, typically Hydrofluoric (HF) and Nitric (HNO₃) acids.

• Purpose:

1. Removes Scale: During hot-forming (e.g., extrusion or annealing heat treatment), a heavy, dark oxide layer (scale) forms on the pipe's surface.
2. Removes Contamination: It dissolves embedded iron particles ("free iron") from tools or handling that can compromise the passive layer and lead to rust staining.
3. Restores Passive Layer: The process dissolves a thin layer of the base metal, which then instantly reacts with oxygen in the air to form a new, continuous, and protective chromium oxide passive layer on the surface.

• Result: A clean, uniform, matte silver-gray surface that is fully corrosion-resistant and ready for service. A pickled surface is a critical quality indicator for high-performance stainless steel.

Apllications

Chemical

Pharmaceutical & Bio-Medical

Petrochemical & Refinery

Environmental

Food Processing

Chemical Fertilizer

Sewage Disposal

Desalination

Waste Incineration etc.