Influence of Alloy Elements on Steel Contraction During Pour
Steel is one of the most widely used metals in the world,and its heat treatment and physical properties mainly depend on its chemical composition,that is,the addition of alloy elements in steel.The different types of alloy elements have different effects on the properties of steel.The effect of alloy elements on steel contraction during pour is mainly caused by the thermal expansion of steel caused by the addition of alloy elements,broadly speaking.
It is well known that when casting,the temperature of molten steel will steadily decline during the pouring process,which will produce a certain degree of thermal contraction of steel.If alloy elements are added to steel during its production process,the contraction of steel during pour will be affected.
In terms of the influence of alloy elements on steel contraction during pour,the most commonly used elements are chrome,silicon,manganese,nickel and molybdenum.The addition of these alloy elements will produce a certain degree of thermal expansion of steel.Chrome and manganese can increase the thermal expansion of steel,silicon and nickel can reduce the thermal expansion of steel,and molybdenum can both increase and reduce the thermal expansion of steel. Therefore,the thermal expansion generated by different alloy elements has a different effect on steel contraction during pour.
When the thermal expansion of steel increases,the contraction of steel during cooling decreases,so the timing of a small contraction occurs late.At the same time,the casting shrinkage of steel gradually decreases from the surface during cooling,which is beneficial for the prevention of casting defects.On the contrary,when the thermal expansion of steel decreases,the contraction of steel during cooling increases,and the casting shrinkage of steel gradually increases from the surface,which is more likely to cause more casting defects.
Moreover,different cutting and machining processes will cause different degrees of shrinkage of steel.For example,the thermal contraction of steel during quenching and tempering is greater than that during normal temperature quenching,and the thermal contraction of steel during high temperature tempering is greater than that during normal temperature tempering.Therefore,when machining,it is necessary to select the appropriate cutting method according to the different uses of the parts in order to reduce the influence of the thermal contraction of steel on the accuracy of the machined parts.
In conclusion,the addition of alloy elements in steel has a certain influence on the contraction of steel during pour.Different alloy elements have different effects on the contraction of steel during pour.Therefore,in order to control the contraction of steel during pour,it is necessary to control the addition of alloy elements in steel in the production process.In addition,the cutting process should be appropriate according to the requirement of the parts machined parts to reduce the influence of thermal contraction on the accuracy of the parts.
