--------We have exported more than 30000 pcs to USA, Germany, Asia, South America, Mid east without complain.

4.we test your crankshaft but hardness less than HRC 40, why

For iron casting crankshaft, we use Nitriding heat treatment. It is not suitable by normal hardness test ( Rockwell hardness). It should test by micro-sclerometer ( Vickers hardness test). please see figure 1.

After you get the V-hardness, please convert it according to the table 1