Vacuum hardening of metal parts

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Advantages and disadvantages of vacuum hardening of metal parts

The surface of the workpiece after vacuum hardening of metal parts is bright, without carburization and decarburization. It can improve the service life of tools and dies that are subjected to friction and contact stress; after vacuum hardening, the size and shape of the workpiece change little, and machining for repairing deformation can be omitted. The workpiece after vacuum hardening has uniform hardness, high mechanical properties and stable quality. Equipment investment is large.

Temperature rise characteristics of vacuum hardening furnace

The self-heating speed of the vacuum hardening furnace is very high when it is empty; the thermal inertia is small; the heat storage and heat dissipation are small.

The temperature rise mainly depends on the achievable heat supply capacity of the charge (the heat obtained by the heated workpiece from the vacuum hardening furnace per unit time and per unit area). In the vacuum hardening furnace, the heat supply capacity is much lower than that of conventional heating with integrated heat transfer in the medium, especially during the heating phase with low radiation efficiency (<600°C) and vacuum tempering heating.

vacuum hardening of steel – a process in which steel is heated above the critical temperature (A, or A3), held for a certain period of time to make it austenitized, and cooled at a rate greater than the critical cooling rate.

Heating speed of steel in vacuum and other media

Heating rate of 50mm×100mm sample of GCr15 steel in different media

1—heating in salt bath, 2—heating in air furnace, 3—heating in vacuum, 1, 2—heating at high temperature; 3—charging at room temperature

Determination of vacuum degree during vacuum heating

Most metals are heated at 500-1350°C, 10-10^-3Pa.

The vacuum degree of the heating process is determined by comprehensively considering the effects of surface brightness, degassing, decarburization and evaporation of alloying elements.

Purpose of vacuum hardening of metal parts:

Improve hardness and wear resistance: knives, measuring tools, abrasive tools

Improve strength and toughness: shafts, rods, pins, force-bearing parts

Improve hard magnetism: Permanent magnets made of high carbon steel and magnetic steel (martensitic magnetism)

Improve elasticity: various springs

Improved corrosion and heat resistance: heat-resistant steel and stainless steel

Applications: thread milling cutters, thread rolling wheels, stepped shafts, mixed rings, hot die tools

Vacuum hardening furnace equipment selection: RVGQ series vacuum hardening furnace produced by SIMUWU company is a high-quality product for vacuum hardening process of metal parts. Good temperature control accuracy and temperature control uniformity ensure the effective vacuum hardening process. The equipment is easy to manage and maintain, greatly reducing maintenance costs.

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