2990 mod. Tool Steel - 1.2990 mod. - ~X100CrMoV8-2 - Data

Heat treatment

2290 mod. is typically air hardened in a vacuum furnace but can also be hardened by using a gas or electric furnace with or without a controlled atmosphere, wrapped in stainless foil or salt bath hardened immersing the work piece in high temperature salts.

Annealing

Heat the material uniformly to a temperature of 1475-1550°F (800-850°C) and hold for 2 hours. Follow this up with a slow cool in the furnace to below 930°F (500°C), then remove it from the furnace and continue cooling in still air to ambient temperature.

Stress relieving

To relive stresses brought on by e.g. heavy machining, heat the part uniformly to a temperature of 1200°F (650°C) and hold 1-2 hours in a neutral atmosphere. Cool slowly in the furnace.

Hardening

Heat uniformly to a temperature of 1900-1940°F (1040-1060°C) and hold for 15-30 minutes. Hardening can be done for example salt bath, compressed air, air and vacuum:

Air hardening

Preheat the material uniformly to a temperature of 1475°F (800°C), then increase the temperature to 1885°F (1030°C). Parts smaller than 1 inch (25.4 mm) can be soaked for up to one hour, parts up to 4 inches (101.6 mm) for 25-30 minutes per inch (25.4 mm). For parts over 4 inches (101.6 mm) thickness in cross section, soaking time should be 10-25 minutes per inch (25.4 mm) of thickness. Then quench with inert gas pressure, for example nitrogen, then cool rapidly with 2 bar atmosphere pressure or high velocity equivalent.

Salt bath hardening

Preheat the part uniformly to 1550°F (850°C) and soak in the molten salt bath at 1885°F (1030°C)for a minimum of 5 minutes. Then quench in salt and let the temperature cool in still air to 120-150°F (45-65°C) before tempering.

Tempering

Double temper 2990 mod. with a cool to ambient temperature between subsequent tempers. For our tempering diagram, please click here.

A third tempering at 750°F (400°C) can be added on to the initial heat treatment, if distortion from machining, surface treatment or EDM is a concern. The third temper is not necessary if parts have been hardened in the salt bath.

Sub-zero treatment

Freezing at a temperature of -300°F (-185°C) between the first and second temper can be beneficial to the toughness of the work piece. Note: Sub-zero treatment should always be followed by a temper.

Surface treatment

To reduce friction and increase wear resistance some cold work tool steels are surface treated using nitriding or surface coating with wear resistant layering like PVD, CVD or TD coating.

Nitriding

Nitriading gives the surface of the material a hard layer with an excellent resistance to wear and galling. To suit the application, the thickness of the layer should be considered well.

PVD coating

Physical vapour deposition (PVD) is a process applying a wear resistant coating to the material/work piece at a temperature range of 390-930°F (200-500°C).

CVD coating

Chemical vapor deposition (CVD) is a process that involves the reaction of a volatile precursor, which is usually injected under vacuum into a chamber. Heating the chamber to reaction temperature, causes the precursor gas to react or break down, which in turn coats and bonds with the material surface.

TD coating

Thermal diffusion (TD) is the process of diffusing zinc into steel to form an anti-corrosive layer at the surface of the steel.

Machinability

Forging

Heat to forge to a temperature of 1650-2010°F (900-1100°C). It is recommended to anneal the work piece after forging to ensure to minimize stresses and optimized heat treatment responses.

Welding

Low pre- and post-heating temperatures, in comparison to D2, will reduce weld cracking and makes welding easier. The low hardness decline, in the affected zones, minimizes any deterioration in its performance.