1： What is cast iron ？

Answer ： Carbon content greater than 2.11％ It's called cast iron 。

2： What kinds of cast iron can be divided into ？

Answer ： White cast iron 、 Gray cast iron 、 Ductile iron 、 Alloy cast iron 、 Malleable iron

3： What are the simple identification methods of iron and steel ？

Answer ： Spark identification 、 Fracture identification 、 Color mark identification 。

4： What is the structure of the alloy ？

Answer ： Solid solution 、 Metal compound 、 Mechanical mixture 。

5： What is the critical point ？

Answer ： Temperature at which metal changes structure 。

6： What is quenching ？

Answer ： Heat the steel to a suitable temperature above the critical temperature ， Rapid cooling after heat preservation to obtain martensitic structure 。

7： What is annealing ？

Answer ； Heat the steel to a certain temperature ， Keep warm for a certain time and then slowly cool to room temperature 。

8： What is hardenability ？

Answer ： The ability of steel to obtain a certain temperature harden layer after quenching under certain conditions 。

9： What is tempering ？

Answer ： Heat the steel to Ac1 A method of cooling to room temperature after the completion of the transformation of the structure 。

10： What is tempering ？

Answer ： It is the heat treatment method combining quenching and high temperature tempering 。

11： What is the purpose of carburizing ？

Answer ： It is to make the active carbon atoms penetrate the steel surface to improve the carbon content of the steel surface 。

12： What is hardness ？

Answer ： It's the ability of steel to maintain its hardness at high temperatures 。

13： Spark identification What are the three kinds of tail flowers in ？

Answer ： Straight tail flower 、 Spear tail 、 Foxtail flower 。

14： What are the functions of electrode ？

Answer ： It can conduct current and provide filler metal to molten pool 。

15： What are the forces on the droplet ？

Answer ： Gravity 、 Surface tension 、 Electromagnetic compression force 、 Spot pressure 、 Plasma force 、 Arc gas force 。

16： What are the defects in gas welding of cast iron ?

Answer ： There are mainly white spots 、 Crackle 、 Refractory oxides, etc 。

17： What is weldability ？

Answer ： Refers to the adaptability of metal materials to welding processing ， It mainly refers to the difficulty of obtaining high-quality welding joints under certain welding process conditions 。

18： What are the main causes of stress and deformation during welding ？

Answer ： It's uneven heating and cooling 。

19： What is primary crystallization ？

Answer ： The process by which the metal in the weld pool changes from liquid to solid

20： There are several forms of riveting ？

Answer ： Mainly overlap 、 Corner joint 、 Docking 。

21： What are the operation procedures of hot riveting ？

Answer ： Fastening and finishing of riveted parts 、 Rivet heating 、 Nailing and threading 、 Top nail 、 Riveting 。