As the thickness and hardness of wear resistant steel sheet NM450 increase, the tendency to crack at the cutting edge increases. In order to prevent the wear resistant steel sheet NM450 from cutting cracks, preheating should be carried out before wear resistant steel sheet NM450 cutting. Special attention should be paid to preheating to make the entire wear resistant steel sheet NM450 interface evenly heated to avoid local overheating in the area contacting the heat source. If the whole wear resistant steel sheet NM450 cannot be preheated, the partial preheating method can be used instead.
India began to implement the national blockade measures on March 25. After two extensions, the national blockade measures have been implemented for nearly 50 days, which has a huge impact on the wear resistant steel sheet NM450 economy. To that end, modi said in a televised speech on the evening of the 12th that India will launch a total of 20 trillion Indian rupees one point eight eight Trillion yuan).
Chromium element (Cr element) can improve the strength and hardness of wear resistant steel sheet NM450, carbon steel in rolling state, reduce elongation and area reduction. When the chromium content is more than 15%, the strength and hardness will decrease, while the elongation and reduction of area will increase correspondingly. It is easy to obtain high surface processing quality for steel parts containing chromium after grinding. The main function of chromium element (Cr element) in quenched and tempered steel structure is to improve hardenability, so that the steel has better comprehensive mechanical properties after quenching and tempering.
The density of wear-resistant plate is higher than that of some materials, wear resistant steel sheet NM450, which makes its hardness larger. The density of steel for wear-resistant plate is 7.85kg/dm cubic. After quenching, martensite structure is obtained and tempered at 450-600℃, or 350-600℃ after tempering at 650℃. Or after tempering at 650℃ and heating at 350-650℃ for a long time, the wear-resistant plate will be embrittled. If the brittle wear-resistant plate is reheated to 650℃ and then cooled quickly, the toughness can be restored, so it is also called reversible temper brittleness. High temperature temper brittleness is the increase of the transition temperature from toughness to brittleness.