431 stainless steel is a stainless steel material with high sulfur content, which belongs to martensitic stainless steel. It has excellent corrosion resistance and high temperature resistance, and has good mechanical properties. 431 stainless steel is usually used to manufacture parts that are highly corrosion-resistant and work in high-temperature environments, such as pump shafts, valves, pressure-bearing parts, etc. It is also commonly used in the manufacture of knives, bearings and auto parts, among others. This material can be heat-treated to increase hardness and strength.
What are the main characteristics of 431 stainless steel?
431 stainless steel is a reinforced stainless steel whose main characteristics include the following:
Good corrosion resistance: 431 stainless steel has good corrosion resistance in common corrosive media, especially good oxidation resistance at high temperatures.
High strength and hardness: 431 stainless steel has high strength and hardness, and can be used in working environments that bear large loads and are resistant to wear.
Excellent mechanical properties: 431 stainless steel has good tensile strength and impact resistance, suitable for engineering applications that require high reliability and durability.
Easy processing and heat treatment: 431 stainless steel has good processing properties, and its strength and hardness can be further improved through the heat treatment process.
Deformation and creep resistance: 431 stainless steel has good deformation and creep resistance under high temperature and high stress conditions, and is suitable for working environments that require long-term stable performance.
Grade 431 stainless steels also have considerable resistance to salt water, but they are less resistant to tropical water than grade 316 steel. The overall corrosion resistance of Grade 431 steel is similar to or slightly lower than that of Grade 304 steel. Grade 431 steel with a smooth surface finish performs well in tempered and hardened conditions.
Other names for 431 stainless steel
material | UNS No | Old British | Euronorm | Swedish SS | Japanese JIS | ||
BS | En | No | Name | ||||
431 | S43100 | 431S29 | 57 | 1.4057 | X17CrNi16-2 | 2321 | SUS 431 |
Chemical composition of 431 stainless steel
material | 431 | ||||||
chemical composition | C | Mn | Si | P | S | Kr | Ni |
≦0.20 | ≦1.00 | ≦1.00 | ≦0.04 | ≤ 0,03 | 15-17 | 1.25-2.50 | |
Mechanical properties of 431 stainless steel
material | 431 | |||
Mechanical Properties
| Zugfestigkeit (MPa) | Yield Strength 0.2% Proof (MPa) | Elongation (% in 50mm) | Hardness Brinell (HB) |
862 | 655 | 20 | ≦285 | |
Physical properties of 431 stainless steel
material | 431 | ||||||||
Physical Properties
| Dichte (kg/m3) | Elastizitätsmodul (GPa) | Mean Coefficient of Thermal Expansion (μm/m/°C) | Wärmeleitfähigkeit (W/mK) | Spezifische Wärme | Electrical Resistivity (nΩ.m) | |||
0-100°C | 0-315°C | 0-538°C | at 100°C | at 500°C | |||||
7800 | 200 | 10.2 | 12.1 | – | 20.2 | – | 460 | 720 | |
Heat resistance of 431 stainless steel
431 stainless steel is a martensitic stainless steel with good heat resistance. 431 stainless steel is resistant to fouling under intermittent conditions at a temperature of 925°C and under continuous operating conditions at a temperature of 870°C. In general, these steels must not be used at temperatures above the standard tempering temperature as they lose mechanical properties
In this temperature range, 431 stainless steel still maintains high hardness and strength. In addition, it also has good oxidation resistance and corrosion resistance.
At high temperatures, the strength and hardness of 431 stainless steel will decrease, but it can still maintain good mechanical properties. It can withstand certain loads and stresses at high temperatures, and is not easily deformed or broken. In addition, the oxidation resistance of 431 stainless steel can also prevent it from being oxidized and damaged at high temperatures.
Annealing process of 431 stainless steel
431 stainless steel is a chromium-nickel martensitic stainless steel with good corrosion resistance and mechanical properties. In some specific applications, 431 stainless steel needs to be heat treated to improve its hardness and strength.
Common heat treatment methods for 431 stainless steel include solution treatment and quenching treatment.
- Complete annealing – 431 stainless steel cannot be fully annealed, and 431 stainless steel will also harden during slow cooling.
- Process annealing – by heating 431 stainless steel to 620 to 660°C, then air cooling.
Grade 431 steel is usually hardened by heating at 980 to 1065°C for approximately ½ hour and then oil quenched or air quenched. Intricate or hardened parts of grade 431 steel can be preheated to temperatures between 760 and 790°C and tempered to improve their mechanical properties. Tempering of these steels between 425 and 600°C should be avoided due to loss of impact toughness in this temperature range.
Processing of 431 stainless steel
431 stainless steel can be easily machined in the annealed condition. However, if the hardness of these steels is higher than 30HRC, it is very difficult to machine. 431 stainless steel is often used in the manufacture of parts that work at high temperatures, such as steam turbine blades, gas turbine blades, etc. It can be processed by the following processing methods:
Forging: 431 stainless steel can be shaped by forging, which can improve its mechanical properties and structural compactness.
Heat Treatment: 431 stainless steel can be heat treated to increase its strength and hardness. Common heat treatment methods include annealing, normalizing, quenching and tempering.
Milling: 431 stainless steel can be milled by a milling machine to cut and modify the surface of the workpiece.
Drilling: You can use a drill press or a drill bit for drilling operations, and select the drilling speed and drill bit blade material according to your needs.
Thread processing: internal and external threads can be processed by thread lathes, including thread milling, thread turning and other processes.
Welding: 431 stainless steel can be used for common welding methods, including manual arc welding, gas shielded welding, TIG welding, etc.
Welding of 431 stainless steel
The welding performance of 431 stainless steel is poor, and cracks may appear during the welding process. The material can be preheated to 200-300°C before welding, and post-weld heat treatment can be performed at 650°C. Various welding methods can be performed, including manual welding, automatic welding and semi-automatic welding.
Application of 431 stainless steel
431 stainless steel is a high-strength stainless steel with good corrosion resistance, suitable for many fields of application.
Manufacturing industry: 431 stainless steel is widely used in the manufacturing industry, such as manufacturing bearings, gears, bolts, valves, connectors, etc.
Knife manufacturing: Since 431 stainless steel has good hardness and strength, it can be used to make knives, such as blades, scissors, saw blades, etc.
Oil and gas industry: 431 stainless steel is used in the oil and gas industry to manufacture valves, pipes and connections.
Medical equipment: Due to its corrosion resistance and anti-wear properties, 431 stainless steel is often used in the manufacture of medical devices, surgical tools, dental instruments, etc.
Food processing: 431 stainless steel has good corrosion resistance and high temperature resistance, and is often used in food processing equipment and container manufacturing.
Summary: 431 stainless steel has a wide range of applications, involving manufacturing industry, tool manufacturing, oil and gas industry, medical equipment, food processing, etc. Due to its excellent corrosion resistance and mechanical properties, 431 stainless steel is one of the commonly used materials in many industries.
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