Factors affecting the hardenability of steel
The main factors affecting the hardenability of steel are: the chemical composition of the steel, the quenching heating temperature, the characteristics of the cooling medium, the method of cooling, the shape and size of the parts, and the heating method.
(1) The chemical composition of steel is one of the most important factors affecting hardenability. All alloying elements that cause the "c" curve to shift to the right or left in steel have a great influence on the hardenability. The element that shifts the "c" curve to the right will increase the hardenability of the steel; the element that shifts the "c" curve to the left will reduce the hardenability of the steel. For example, 45 steel and 40Cr steel have similar carbon content. However, since the former does not contain chromium, the latter contains about 1% of chromium. Under the same heat treatment conditions, their hardenability is obviously different. 45 steel only It can be hardened by 3.5-9.5 mm, while 40Cr steel can be hardened by 25-32 mm.
(2) The cooling characteristics and cooling rate of the heat treatment cooling medium also have a great influence on the hardenability of the steel. When the cooling rate is fast, the hardenability is improved, and the cooling rate is lowered, and the hardenability is lowered. For example, 45 steel is cooled in water and cooled in oil, and its hardenability is different. When it is cooled in water, it can be hardened by 11-20 mm, and when cooled in oil, it can be hardened by 3.5-9.5 mm.
(3) The shape and size of the parts, heating temperature, cooling method, etc., affect the hardenability of the steel to varying degrees. The shape size is small, the heating temperature is high, and the continuous cooling can improve the hardenability to some extent. However, the shape size is large, the heating temperature is low, and the isothermal cooling can reduce the hardenability.
(4) The way of heating also affects the hardenability, which is very important in practical operation, and we tend to ignore this. The heating effect is different because of the different heating methods. For example, the use of a box type electric furnace is more serious than the oxidation and decarburization of the salt bath furnace, and the hardenability is lowered.
(1) The chemical composition of steel is one of the most important factors affecting hardenability. All alloying elements that cause the "c" curve to shift to the right or left in steel have a great influence on the hardenability. The element that shifts the "c" curve to the right will increase the hardenability of the steel; the element that shifts the "c" curve to the left will reduce the hardenability of the steel. For example, 45 steel and 40Cr steel have similar carbon content. However, since the former does not contain chromium, the latter contains about 1% of chromium. Under the same heat treatment conditions, their hardenability is obviously different. 45 steel only It can be hardened by 3.5-9.5 mm, while 40Cr steel can be hardened by 25-32 mm.
(2) The cooling characteristics and cooling rate of the heat treatment cooling medium also have a great influence on the hardenability of the steel. When the cooling rate is fast, the hardenability is improved, and the cooling rate is lowered, and the hardenability is lowered. For example, 45 steel is cooled in water and cooled in oil, and its hardenability is different. When it is cooled in water, it can be hardened by 11-20 mm, and when cooled in oil, it can be hardened by 3.5-9.5 mm.
(3) The shape and size of the parts, heating temperature, cooling method, etc., affect the hardenability of the steel to varying degrees. The shape size is small, the heating temperature is high, and the continuous cooling can improve the hardenability to some extent. However, the shape size is large, the heating temperature is low, and the isothermal cooling can reduce the hardenability.
(4) The way of heating also affects the hardenability, which is very important in practical operation, and we tend to ignore this. The heating effect is different because of the different heating methods. For example, the use of a box type electric furnace is more serious than the oxidation and decarburization of the salt bath furnace, and the hardenability is lowered.
Corrugated Testing Equipment,Cardboard Puncture Tester,Crush Tester,Box Compression Strength Tester
Dongguan Hengke Automation Equipment Co., Ltd. , https://www.hengkeinstrument.com