Reduced temperature steel has exceptional toughness and durability in low temperature atmosphere, good welding performance, machining efficiency and rust resistance, are typically defined in the minimum temperature level of a particular value of effect sturdiness in the standard. In reduced temperature level steels, elements such as carbon, silicon, phosphorus, sulfur as well as nitrogen degrade the strength at reduced temperature, amongst which phosphorus is considered to be the most dangerous and ought to be dephosphorized at low temperature level in very early smelting. Mn, nickel and other aspects can enhance the toughness at low temperature. With the boost of nickel web content by 1%, the critical transition temperature level of brittleness can be lowered by about 20 ℃. Reduced temperature level durability, i.e. the capacity to prevent breakable failing from taking place and also spreading at low temperatures, is the most vital factor. Today we introduce the impact of alloying elements on the low temperature strength of steel:

C.

With the boost of carbon content, the breakable shift temperature level of steel increases swiftly and also the weldability decreases, so the carbon material of low-temperature steel is limited to much less than 0.2%.

Mn.

The manganese exist in steel with the kind of solid solution as well as can undoubtedly improve the sturdiness of steel at reduced temperature. In addition, manganese is an element that expands the Austenite area and reduces the transformation temperature (A1 and A3). It is very easy to get great and also ductile ferrite as well as pearlite grains, which can make best use of the effect energy as well as lower the weak change temperature level. Therefore, the Mn/C ratio should go to least equivalent to 3, which can not only lower the fragile shift temperature of steel, but also make up for the reduction in mechanical homes brought on by the decline in carbon material due to the boost of Mn.

Ni.

Nickel can reduce the brittleness tendency and dramatically reduce the breakable change temperature level. The impact of nickel on boosting the low temperature level strength of steel is 5 times that of manganese. The weak shift temperature level lowers by 10 ℃ with the rise of nickel web content by 1%. This is due to the fact that the nickel does not respond with carbon, however all dissolved right into the solid service and the strengthening, nickel additionally makes the steel eutectoid indicate the wldsteel lower left, as well as minimize the eutectoid point of carbon content and phase modification temperature level (A1 and A2), so compared with other carbon steel has the very same carbon web content, the variety of ferrite decrease and also refinement, while the pearlite rise.

P 、 S 、 Pt 、 Pb 、 Sb.

These components are detrimental to the reduced temperature level toughness of steel. They create segregation in steel, which reduces the surface power of grain boundary, minimizes the resistance of grain border, and also creates the breakable split to stem from grain border and also proliferate along grain border until the fracture is total.

Phosphorus can enhance the toughness of steel however enhance the brittleness of steel, specifically the brittleness at low temperature. The weak transition temperature is certainly increased, so the web content of phosphorus ought to be purely restricted.

H, O, N.

These elements will certainly boost the breakable shift temperature level of steel. Low temperature toughness can be improved by deoxidizing eliminated steels with silicon and also aluminum. However silicon raises the brittle change temperature of steel, so light weight aluminum eliminated steel has a lower breakable shift temperature than silicon eliminated steel.