440B Stainless Steel – Data Sheet, Applications, Hardening
The material 440B is a martensitic chromium steel, which is also known under the designations EN 1.4112 and the DIN designation X90CrMoV18. Due to its good hardenability, polishability and corrosion resistance, the material is often used for knife blades. It is similar to the materials 1.4125 (AISI 440C) and 1.4109 (AISI 440A), but differs in its carbon content. This is higher in this stainless steel grade than in 1.4109, but lower than in 1.4125. Thus, 440B steel exhibits medium hardness compared to the AISI 440C and AISI 440A materials.
Chemical composition – data sheet
440B stainless steel is characterized by a high chromium and carbon content. As a result, the material exhibits high hardenability and moderate corrosion resistance.
| C | Si | Mn | P | S | Cr | Mo | V |
| 0.85 – 0.95% | ≤ 1 % | ≤ 1 % | ≤ 0.04% | ≤ 0.015% | 17 – 19% | 0,9 – 1.3% | 0,07 – 0.12 % |
Properties and advantages
Due to the high carbon content, the stainless steel is unsuitable for most welding operations. The weldability of this material is so poor because hardening cracks can form during welding.
440B steel is magnetizable. For this reason, it is often used in cutting tools and instruments. In addition, the material is characterized by very good polishability, high wear resistance and excellent hardness.
Areas of application
One of the most common areas of application for 440B is in the cutlery industry. Due to its given mechanical properties, it is used as a material for blades and cutting edges. In addition, 440B is also used in the following industries:
- Mechanical engineering
- Construction industry
- Drive technology
- Pump industry
- Tool and mold making
In food technology and medical technology, 440B is also used. Its durability, polishability and resistance to corrosion make it a very good material for tools and instruments in these fields.
Hardening of 440B
The hardness of 440B is between 265 – 299 HB, depending on the delivery condition. The steel can be hardened very well by heat treatment. The stainless steel can be hardened at temperatures between 1000 and 1050 °C. This is followed by quenching in oil, in the air or in a hot bath. If this is desired, tempering can be carried out at temperatures between 100 and 500 °C to reduce stresses in the material. Higher tempering temperatures can have a negative effect on hardness.
In addition to conventional heat treatment, 440B can also be treated using the BORINOX® process for hardening stainless steel. The special compound layer additionally protects the material and offers protection against corrosion, abrasion and cavitation in addition to the extremely high hardness. The process enables the 440B material to achieve higher thermal resistance and better stability against acids.
