Quenching distortion or cracking
Strictly enforce the correct heat treatment, heating temperature, check the temperature control, ensuring consistent uniform temperature, as well as other measures taken to preheat; choose a reasonable cooling medium and the quenching method using pre-cooled or fractionated or isothermal hardening ; Choose qualified high-pressure seamless tube as organization and composition; adequate and timely tempering; improve design, reduce stress concentration, or the poor parts of the cross-section to be protected.

Insufficient hardness 
Strictly enforce the requirements of heat treatment process to prevent subcritical quenching; a reasonable choice of the cooling medium and cooling methods, or choose to meet the requirements of the raw materials used in salt bath furnace or protective atmosphere furnace heating parts, to avoid changing the chemical composition of the surface.

Uneven hardness
Strictly controlled atmosphere within the furnace, to ensure a neutral or substantially reducing; to maintain all parts of the surface cleaning and processing; cooling medium should be able to meet the needs of quenching, while circulating flow and timely filtration.