Activity

Reduced temperature steel has superb stamina and also durability in low temperature level setting, excellent welding efficiency, machining performance and also corrosion resistance, are typically defined in the minimum temperature of a specific worth of effect toughness in the standard. In low temperature level steels, components such as carbon, silicon, phosphorus, sulfur and nitrogen deteriorate the toughness at reduced temperature level, among which phosphorus is taken into consideration to be one of the most dangerous and also must be dephosphorized at reduced temperature in very early smelting. Mn, nickel and other components can improve the durability at low temperature. With the increase of nickel material by 1%, the critical transition temperature level of brittleness can be reduced by about 20 ℃. Reduced temperature level strength, i.e. the capability to prevent breakable failing from occurring and also spreading out at reduced temperature levels, is the most vital factor. Today we present the impact of alloying elements on the low temperature level durability of steel:

C.

With the boost of carbon material, the fragile change temperature of steel boosts quickly and also the weldability reduces, so the carbon web content of low-temperature steel is limited to less than 0.2%.

Mn.

Wldsteel exist in steel with the form of solid remedy and can undoubtedly enhance the strength of steel at reduced temperature. Furthermore, manganese is an element that increases the size of the Austenite region as well as lowers the improvement temperature level (A1 and A3). It is easy to obtain fine as well as ductile ferrite and also pearlite grains, which can take full advantage of the impact energy as well as lower the breakable change temperature. Because of this, the Mn/C proportion should be at least equivalent to 3, which can not only decrease the fragile shift temperature level of steel, yet also compensate for the decline in mechanical residential properties triggered by the decrease in carbon content because of the rise of Mn.

Ni.

Nickel can decrease the brittleness propensity and also significantly reduce the breakable transition temperature. The result of nickel on enhancing the reduced temperature durability of steel is 5 times that of manganese. The weak transition temperature lowers by 10 ℃ with the boost of nickel material by 1%. This is due to the fact that the nickel does not respond with carbon, but all dissolved right into the solid remedy as well as the strengthening, nickel additionally makes the steel eutectoid point to the reduced left, and also minimize the eutectoid point of carbon material as well as phase modification temperature level (A1 and A2), so compared with other carbon steel has the very same carbon content, the number of ferrite decrease and improvement, while the pearlite rise.

P 、 S 、 Pt 、 Pb 、 Sb.

These aspects are destructive to the low temperature level strength of steel. They generate partition in steel, which decreases the surface area power of grain border, reduces the resistance of grain border, and also causes the fragile split to stem from grain limit and propagate along grain border till the crack is complete.

Phosphorus can improve the strength of steel but enhance the brittleness of steel, especially the brittleness at reduced temperature level. The fragile shift temperature level is clearly enhanced, so the web content of phosphorus need to be purely limited.

H, O, N.

These elements will raise the weak shift temperature of steel. Low temperature durability can be boosted by deoxidizing killed steels with silicon and light weight aluminum. Yet silicon enhances the fragile change temperature level of steel, so light weight aluminum eliminated steel has a lower fragile change temperature than silicon eliminated steel.