请帮我把这几句话翻成英文,1.了解了扭转实验机的构造原理,并学习了操作.2．学习了如何测定低碳钢的剪切屈服极限、剪切强度

1. understand the aufbau principle of Torsional experiment machine, and learn to process.
2. learn how to test shear yield limit, shear ultimate tensile strength of mild steel and shear ultimate tensile strength of cast iron.
3. observe the deformation and destruction of mild steel and cast iron during torsion processing.l
in the actual engineering machinery, numbers of transmission are under torsion processing, after this experiment, i have got a comprehensive knowledge about properties of cast iron and mild steel (tension, compression, torsion, bend). cast iron show brittleness and mild steel show toughness. the plasticity of mild steel is better than cast iron because its ultimate tensile strength is larger, and it can be used to made rivet. cast iron is short of plasticity and easily broke, so it need to be keep balance to avoid initial torque.