The quenching crack of mould steel defects：1.shape effect.2.Overheat.3.Decarbonization.4.Improper cooling5.Poor organization of raw materials
The quenching crack of mould steel defects
Causes of quenching and preventive measures are as follows:
1. Shape effect.It is mainly caused by design,such as too small rounded Angle R, improper hole location and bad section transition.
2. Overheat (overheat).It is mainly caused by temperature control inaccuracy or running temperature, process setting temperature is too high, furnace temperature is not equal factors, preventive measures include: maintenance, proofreading temperature control system, correction process temperature, in the workpiece and the bottom plate of the furnace pad, etc.It also cause the crack of mould steel defects
3. Decarbonization.Mainly caused by overheating (or over burning), unprotected heating of the air furnace, small machine allowance, forging or preparation heat treatment residual decarburization layer and other factors, the preventive measures are: controlled atmosphere heating, salt bath heating, vacuum furnace, box type furnace use packing protection or use anti-oxidation coating;Increase machining allowance by 2-3mm.
4. Improper cooling.It is mainly caused by improper coolant selection or supercooling, should master the cooling characteristics of the quenching medium or tempering treatment.
5. Poor organization of raw materials.If the carbide segregation is serious, the forging quality is poor, the preparation heat treatment method is not appropriate, the preventive measures are: adopt the correct forging technology and the reasonable preparation heat treatment system。
Here is some of the mould steel defects，I would like to suggest you to contact me to know more about mould steel,such as 1.2738–1.2344–D2，It will help you with avoiding much trouble.
And I would like to share some chemical information for your reference.
1.2344 Tool Steel Chemical composition
| C(％) | 0.37～0.42 | Si(％) | 0.90～1.20 | Mn(％) | 0.30～0.50 |
| P(％) | ≤0.030 | S(％) | ≤0.030 | Cr(％) | 4.80～5.50 |
| Mo(％) | 1.20～1.50 | V(％) | 0.90～1.10 |
D2 steel Related Specifications In American steel standard A681-1999
D2 Tool steel Chemical composition
| C(％) | 1.40～1.60 | Si(％) | 0.10～0.60 | Mn(％) | 0.20～0.60 |
| P(％) | ≤0.030 | S(％) | ≤0.030 | Cr(％) | 11.0～13.0 |
| Mo(％) | 0.70～1.20 | V(％) | 0.50～1.10 |
1.2738 Tool steel Chemical composition
| C | Si | Mn | P | S | W | Cr | V |
| 0.35～0.45 | 0.20～0.40 | 1.30～1.60 | 0.035 max | 0.035 max | 1.80～2.10 | 1.80～2.10 | ~ |
Ms Sharon Wan
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Email: Sharon@otaisteel.com
