Tempered steel
Tempering steel is steel , by tempering (= hardening and tempering ) high tensile and fatigue strength is obtained. The toughness is determined by the ratio of hardness (depending on the material, selected hardening temperature and selected quenching speed) and temperature of the subsequent tempering process. It is a transformation hardening in which the ratio of strength to toughness is specifically influenced.
The carbon content is between 0.2 and 0.65%. The different alloy contents of chromium , manganese , molybdenum and nickel are matched very precisely to the respective application and have a special influence on larger cross-sections. The hardenability of steels, inter alia, with the end-quench by Jominy determined.
( Quenched and tempered steels; see DIN EN 10083)
Quenched and tempered steel is used for crankshafts , axles , shafts , connecting rods , bolts , screws and other structural parts of higher strength, such as aircraft landing gear (tensile strength up to 2000 MPa).
With regard to the weldability of quenched and tempered steels, it should be noted that due to the carbon content, local hardening in the weld zone must be expected. Therefore, it usually has to be preheated and reheated.
Examples
- The steel of the specification C45E is a quenched and tempered steel with 0.45% carbon. The E stands for a particularly low content of phosphorus (≤0.025%) and sulfur (≤0.035%). C45E is called Ck 45 according to the outdated standard.
Machinability
See machinability of steel .
Individual evidence
- ↑ Data sheet C45E (PDF; 677 kB)