(1) hardness is the main technical index of mold steel, and the mould must be sufficient to keep its shape and size unchanged under the effect of high stress.
High hardness. Cold made mold steel at room temperature, the general hardness is maintained at HRC60, and the heat is made by steel according to its working conditions, general requirements.
Stay in the HRC40~55 range. For the same steel, the hardness is proportional to the deformation resistance in a certain range of hardness. But it's the same
There may be obvious differences in the plastic deformation resistance between different types of steel.
(2) the hot working mold of red and hard working at high temperature requires maintaining the stability of its organization and performance, so as to maintain a high enough hardness.
This performance is called red hardness. Carbon tool steel, low alloy tool steel can often in 180 ~ 250 ℃ temperature range of this kind of performance, chrome
Molybdenum thermal die steel generally maintains this performance within the temperature range of 550~600. The hardness of steel depends mainly on the chemical composition and heat of steel.
(3) the compressive yield strength and compressive bending strength die are often subjected to high pressure and bending in the process of use, therefore.
It is required that the mould materials should have certain compressive strength and flexural strength. In many cases, the conditions for conducting compression tests and bending tests are close to.
The actual working conditions of the molds (for example, the pressure yield strength of the measured die steel and the deformation resistance shown in the punch work are more kiss.
Us). Another advantage of the bending test is that the absolute value of the variable is large, which can reflect the different kinds of steel and the different heat treatment.
The difference of deformation resistance under organizational condition.
In the process of working, the mold bears the impact load, and in order to reduce the damage in the process of fracture and collapse, the mold is required.
Steel has a certain toughness.
The number, morphology, size and distribution of the chemical composition, grain size, purity, carbides and inclusions of die steel, as well as.
The heat treatment system of die steel and the metallographic structure obtained after heat treatment have great influence on the toughness of steel. Especially the purity of steel.
The effect of thermal deformation on transverse toughness is more obvious. The toughness, strength and wear resistance of steel are often contradictory. As a result,
It is necessary to choose the chemical composition of steel reasonably and adopt reasonable refining, heat treatment and heat treatment process to make the mold material wear resistance and strength.
Toughness achieves optimal cooperation.
The total energy absorbed by the test sample during the whole fracture process during the process of the impact toughness. But many tools are not.
Because of fatigue fracture under working conditions, conventional impact toughness cannot fully reflect the fracture performance of die steel. Small energy multiple impact break.
Test techniques such as crack or multiple fracture life and fatigue life are being used.