Vacuum marquenching treatment (RV treatment)

We perform the heat treatment of small and large hot work die steels (SKD-61, etc.) normally used for die casting dies and various forging dies.
Treating large dies with a conventional pressurized nitrogen gas cooling method tends to create problems such as uneven hardness, distortion and deformation due to insufficient cooling.

Metal Heat Co., Ltd. has developed a new heat treatment method to ensure uniform hardness, reduce distortion and improve the life span of dies by enhancing technology licensed from Daido Steel and Daido Amister.
All processes are treated in a vacuum environment. This is RV treatment.

(*) Effective size H 600 mm x W 600 mm x L 1,050 mm

Reduction of distortion

Since the foundation of our company, correcting distortion after heat treatment had an important role. However, it is very difficult to pin point the cause of distortion because distortion varies depending on the material and the shape of products.
We now put more effort into reducing distortion by reviewing the material and design of products, examining the best pretreatment method, arranging the products in a furnace, selecting a furnace and setting the heat treatment conditions using our abundant experience in this field.
After quenching, we apply the most suitable method of correction in an optimized manner depending on the amount of distortion.
We make every effort to further improve quality to make "Metal Heat Co., Ltd. the leading company in the heat treatment industry".

Factors of distortion during heat treatment

While heating up…Releasing and removing internal stress
While maintaining the temperature…Gravity sagging by product’s size and length
While cooling…Cooling transformation

Factors of distortion from the designing stage to finishing touch stage

(Design)
　The problem of shape

(Material)
　Material selection problem

(Primary processing)
　Covered with mill scales
　Remaining mill scales (ground only on one side)

(Secondary processing)
　Residual stress from high-speed machining
　Residual stress from heavy cutting
　Residual stress from padding or flame hardening

(Heat treatment)
　From heat treatment

(Finishing touch)
　Thermal effect of polishing, etc.
　Thermal effect of wire cut, electrical discharge machining, etc.