Description

,Our core business including:
 
1, provide liquid nitriding heat treatment agent nitriding salt,
2, salt bath nitriding technology transfer service,
3, provide nitriding heat treatment service for customers.
 
QPQ means quench, polish, quench and consists of salt bath nitrocarburizing followed by oxidative cooling, mechanical polishing, lapping or vibratory finishing and brief re-immersion into the oxidising salt melt. The end result gives unalloyed and low alloyed steels, a lustrous black finish with corrosion resistance which is superior in many cases to surfaces developed by galvanic or chemical processes.

Salt bath ferritic nitrocarburizing is also known as liquid nitriding or liquid nitrocarburizing or salt bath nitriding, it is a range of case hardening processes that diffuse nitrogen and carbon into ferrous metals at sub-critical temperatures. it is usually carried out between **0°C and **0°C, with treatment times in the order of *0 minutes to 3 hours. In some cases, salt bath nitrocarburising can be used as an alternative to other surface zone processes such as case hardening or hard chromium plating with equal or improved effectiveness and greater economy
The process is used to improve three main surface integrity aspects:
wear resistance
fatigue strength
corrosion resistance
It has the added advantage of inducing little shape distortion during the hardening process. This is because of the low processing temperature, which reduces thermal shocks and avoids phase transitions in steel
The process uses a salt bath of alkali cyanate. This is contained in a steel pot that has an aeration system. The cyanate thermally reacts with the surface of the workpiece to form alkali carbonate. The bath is then treated to convert the carbonate back to a cyanate. The surface formed from the reaction has a compound layer and a diffusion layer. The compound layer consists of iron, nitrogen, and oxygen, is abrasion resistant, and stable at elevated temperatures. The diffusion layer contains nitrides and carbides. The surface hardness ranges from **0 to ***0 HV depending on the steel grade. This also inversely affects the depth of the case; i.e. a high carbon steel will form a hard, but shallow case
These processes are most commonly used on low-carbon, low-alloy steels, however they are also used on medium and high-carbon steels. Common applications include spindles, cams, gears, dies, hydraulic piston rods, and powdered metal components.
 
Our typical materials test result and process specifications are as follows: