Reduced temperature steel has excellent strength as well as strength in low temperature atmosphere, excellent welding performance, machining performance as well as deterioration resistance, are typically specified in the minimum temperature level of a specific value of impact strength in the requirement. In reduced temperature steels, elements such as carbon, silicon, phosphorus, sulfur and nitrogen wear away the durability at low temperature, among which phosphorus is taken into consideration to be the most harmful and ought to be dephosphorized at low temperature level in very early smelting. Mn, nickel and also various other components can boost the toughness at reduced temperature. With the boost of nickel content by 1%, the vital change temperature level of brittleness can be minimized by around 20 ℃. Reduced temperature strength, i.e. the capability to stop fragile failure from happening and also spreading at low temperatures, is the most vital element. Today we present the influence of alloying components on the reduced temperature strength of steel:
C.
With the boost of carbon material, the breakable change temperature of steel boosts swiftly and also the weldability decreases, so the carbon content of low-temperature steel is limited to much less than 0.2%.
Mn.
The manganese exist in steel with the form of strong option as well as can clearly enhance the durability of steel at low temperature. On top of that, www.wldsteel.com manganese is a component that increases the size of the Austenite area and also decreases the transformation temperature (A1 as well as A3). It is very easy to get great as well as pliable ferrite and also pearlite grains, which can optimize the influence power as well as decrease the weak shift temperature level. Therefore, the Mn/C proportion need to be at the very least equal to 3, which can not only minimize the fragile change temperature of steel, however additionally compensate for the decline in mechanical residential or commercial properties caused by the decline in carbon material as a result of the boost of Mn.
Ni.
Nickel can reduce the brittleness tendency and also significantly lower the weak change temperature level. The result of nickel on boosting the low temperature sturdiness of steel is 5 times that of manganese. The brittle transition temperature level decreases by 10 ℃ with the boost of nickel content by 1%. This is due to the fact that the nickel does not react with carbon, however all liquified into the solid remedy and also the fortifying, nickel likewise makes the steel eutectoid point to the reduced left, as well as lower the eutectoid point of carbon content as well as phase change temperature level (A1 and A2), so compared with various other carbon steel has the exact same carbon content, the variety of ferrite reduction and improvement, while the pearlite rise.
P 、 S 、 Pt 、 Pb 、 Sb.
These aspects are detrimental to the low temperature sturdiness of steel. They produce partition in steel, which decreases the surface area power of grain boundary, reduces the resistance of grain boundary, and triggers the brittle crack to originate from grain limit and also proliferate along grain border till the crack is full.
Phosphorus can enhance the stamina of steel but boost the brittleness of steel, particularly the brittleness at low temperature level. The weak change temperature is obviously increased, so the web content of phosphorus should be strictly limited.
H, O, N.
These elements will enhance the breakable transition temperature of steel. Reduced temperature level sturdiness can be boosted by deoxidizing eliminated steels with silicon and also light weight aluminum. However silicon boosts the fragile shift temperature level of steel, so aluminum eliminated steel has a reduced breakable transition temperature level than silicon killed steel.