Which auto tool is the good tool?

Many people think the high price is the best tool.but Good tools not only know with price only,the material,production technic,surface treatment also are main key of the price and good or bad tool.For ex

No.1     Material:

In the Chinese market,There are A3,45#,40CR three type steel material.

                        GB                    JIS                    ASTM                              DIN

A3                 Q235                 SS41                   A283-C                         17100 

45#               45#                   S45C                   SAE 1045                        C45

40cr             40CR                SCr440                SAE 5140                        41CR4

Report:

A3 

                  

45#    

           

40CR 

     

SO,The price from cheap to expensive is   A3 <45#<40cr and heavy duty

NO.2        Technic

Forge drop or casting is the main technic in tool manufacturing. and forge drop will be more expensive than casting,meanwhile,Forge drop will be better in the quality and heavy duty.

No.3       Heat treatment

Many auto tools work in heavy duty job.so if the tools' HRC Hardness is high,the tool will be better. A3 steel can't heat treatment,and there is no HRC hardness,is not a good material for tools. After treatment, The 45# max hardness is 35-45,The 40CR is 40-55.but more attention:too high HRC hardness the steel will be broken easy,so 38-42 is the better.

No.4     Surface treatment

In the Chrome plated,black oxide coating,electrophoretic paint,zinc plating,phosphorization,Chrome plated is more expensive than others.

So, if a tool is the 40cr or 45#, Forge drop treatment, HRC hardness  about 40, chrome plated is the better tools. 

Thanks for DNT Tools offered the knowledge.