Microalloyed steel发表评论(0)编辑词条

Microalloyed steel

Microalloyed steel is a type of alloy steel that contains small amounts of alloying elements (0.05 to 0.15%). Standard alloying elements include: niobium, vanadium, titanium, molybdenum, zirconium, boron, and rare-earth metals. They are used to refine the grain microstructure and/or facilitate precipitation hardening.

These steels performance and cost land between carbon steel and low alloy steel. Yield strength is between 500 and 750 MPa (73,000 and 110,000 psi) without heat treatment. Weldability is good, and can even be improved by reducing carbon content while maintaining strength. Fatigue life and wear resistance are superior to similar heat treated steels. The disadvantages are that ductility and toughness are not as good as quenched and tempered (Q&T) steels. They must also be heated hot enough for the all of the alloys to be in solution; after forming the material must be quickly cooled to 540 to 600 °C (1000 to 1100 °F).

Cold worked microalloyed steels do not require as much cold working to achieve the same strength as other carbon steel; this also leads to greater ductility. Hot worked microalloyed steels can be used from the air cooled state. If controlled cooling is used, the material can produce mechanical properties similar to Q&T steels. Machinability is better than Q&T steels because of their more uniform hardness and their ferrite-pearlite microstructure.

Because microalloyed steels are not quenched and tempered they are not susceptible to quench cracking, nor do they need to be straightened or stress relieved. However, because of this they are through hardened and do not have a softer and tougher core like quench and tempered steels.

微合金钢
　　微合金化的高强度低合金钢。
　　它是在普通软钢和普通高强度低合金钢基体化学成分中添加了微量合金元素(主要是强烈的碳化物形成元素，如Nb、V、Ti、A1等)的钢，合金元素的添加量不多于0.20％。添加微量合金元素后，使钢的一种或几种性能得到明显的变化。
　　典型的微合金钢有15MnVN和06MnNb。微合金钢中含有一种或几种微合金元素，其含量大约在0.01％～0.20％之间。
　　微合金钢由于屈服强度高、韧性好、焊接性和耐大气腐蚀性好，可用于大型桥梁建筑，制造各类车辆的冲压构件、安全构件、抗疲劳零件及焊接件，它也是锅炉、高压容器、输油和输气管线，以及工业和民用建筑的理想材料。