工字钢也称为钢梁（英文名称 I Beam)，是截面为工字形状的长条钢材。工字钢分普通工字钢和轻型工字钢，H型钢三种。工字钢广泛用于各种建筑结构、桥梁、车辆、支架、机械等。

I-steel beam (also known as English name I Beam), is an H-shaped steel strip section. I-steel is divided into three kinds: ordinary I-steel and light I-steel, H type steel. I-steel is widely used in various architectural structures, bridges, vehicles, stents, machinery and so on.

型材按使用部门分类有铁路用型材（钢轨、鱼尾板、道岔用轨、车轮、轮箍）、汽车用型材（轮辋、轮胎挡圈和锁圈）、造船用型材（L型钢、球扁钢、Z字钢、船用窗框钢）、结构和建筑用型材（H型钢、工字钢、槽钢、角钢、吊车钢轨、窗框和门框用材、钢板桩等）、矿山用钢（U型钢、槽帮钢、矿用工字钢、刮板钢等）、机械制造用异型材等。在结构形式上有二辊式轧机、三辊式轧机、孔型轧机、多辊孔型轧机、Y型轧机、45°轧机和悬臂式轧机等。按断面尺寸大小分类。

合金元素与铁、碳的相互作用

合金元素加入钢中后，主要以三种形式存在钢中。即：与铁形成固溶体；与碳形成碳化物；在高合金钢中还可能形成金属间化合物。

The interaction of alloying elements with iron and carbon

When alloy elements are added to steel, they mainly exist in three forms. Namely: to form a solid solution with iron; carbide and carbon; in high alloy steels are also likely to form intermetallic compounds.

细木工板握螺钉力好，强度高，具有质坚、吸声、绝热等特点，而且含水率不高，在10%—13%之间，加工简便，用途为广泛。

The woodworking board has good grip strength, high strength, strong quality, sound absorption, insulation and other characteristics, and water content is not , between 10% - 13%, easy processing, the most widely used.