300 Series Heat Resistant Stainless Steel Plates

310/310S Alloy (UNS S31000/S31008)

This austenitic stainless steel alloy is primarily used in high-temperature environments. Its high chromium and nickel content ensures good corrosion and oxidation resistance, providing higher strength at room temperature compared to the austenitic 304 alloy.

General Properties

309/309S and 310/310S Alloys: Commonly used in high-temperature environments, offering excellent corrosion and oxidation resistance with higher strength than the 304 alloy.

Aplicaciones

Heat Treatment Industry: Used in furnace parts like conveyor belts, rollers, furnace heads, refractory pads, and pipe hangers due to high-temperature strength, creep resistance, and environmental corrosion resistance.
Chemical Processing Industry: Handles hot concentrated acids, ammonia, and disulfides.
Food Processing Industry: Used with hot acetic and citric acids.

Resistance to Aqueous Solutions

Resistencia a la corrosión: High chromium and nickel content provide some resistance to aqueous solutions.
Chloride Stress Cracking: More resistant than 18-8 stainless steel but still susceptible.

High-Temperature Oxidation Resistance

Oxidation: Chromium forms a stable oxide layer (Cr2O3) that protects the metal. High nickel content also improves performance at high temperatures.
Measurement: Resistance to oxidation can be measured by weight change after exposure to high temperatures.
Spalling: Can cause rapid weight loss due to thermal cycling, mechanical damage, and excessive oxide thickness.

Other Forms of Degradation

Sulfidation Corrosion: Enhanced by high sulfur and oxygen content, particularly in high nickel alloys.
Carburization: Occurs at temperatures above 1470°F (800°C), leading to internal carbides and mechanical property changes.
Nitriding: Can occur in pure nitrogen environments, forming internal nitrides that affect mechanical properties.

Metallographic Instabilities

Sensitization: Precipitation of carbide particles at grain boundaries in the temperature range of 800-1650°F (427-899°C).
Sigma Phase: Reduces ductility at temperatures of 1200-1850°F (649-1010°C).

Processing Characteristics

Forming: More difficult to process and harden quickly compared to carbon steel.
Cutting and Machining: Requires sharp, hard tools with deep and slow cuts to manage hardened areas.
Cold Working: Techniques like bending, stretch forming, and roll forming are used, but powerful equipment is needed due to work hardening.

Welding

Weldability: Austenitic grades are highly weldable by all common methods.
Filler Solder: Use composition-matched solder or silicon-containing solder for better fluidity.
Thermal Expansion and Conductivity: Higher coefficients may cause hot cracking; low-alloy content solder can reduce this risk.
Post-Welding: Remove temper color and rust by grinding, brushing, or pickling.

Heat Treatment/Annealing

Annealing: Produces a recrystallized microstructure, uniform grain size, and decomposes harmful carbide precipitates. Requires exposure to 2050-2150°F (1120-1175°C).
Scale Removal: Combination of mechanical and chemical methods, such as sandblasting and pickling with nitric and hydrofluoric acids.

Resumen

309/309S and 310/310S stainless steels are ideal for high-temperature and high-corrosion environments, providing strong resistance to oxidation, carburization, and other forms of degradation. They are widely used in various industries, from heat treatment to chemical processing, due to their excellent mechanical properties and resistance characteristics.