42CrMo Hydraulic Cylinder Piston Hollow Rods Hard Chrome Plated Steel Bar NSS 500 Hours

Material :42CrMo

Color :Black

NSS:Endure 300;500;800hours

Type:Hollow/Solid Rod

Application Environment:At sea or in harsh environments

Surface hardness:＞HV860

SURFACE ROUGHNESS:Ra≤0.2 micron and Rt≤2 micro

TOLERANCES ON DIA:ISO f10 on the diameter

Testing Standing une-en iso9227:2017

· Sal solution: 50 (+/- 5) g/l of NaCl. Water is demineralized and salt purity is 99.5%.

· Environmental temperature: 35 °C.

· pH of salt solution is 6.8.

· Volumen of salt solution is 38.4 ml/day.

· Density of salt solution is 1,030 g/cm3.

· Spraying is 1.5 (+/- 0.5) ml/h.

Test Result :NSS can endure 300 hours ;500 hours; 800 hours

SGS NSS Testing Report                       TUV NSSTesting Repopt 

Heat treatment

2. After quenching, put into the oil tank to cool from the box furnace

3. After cooling, the first time tempering: tempered at 640 °C and the hardness is controlled at about HRC28-32, the first time tempering cooling is used Water-cooled.

4. Straightening: The outer circle is controlled by 200 um(0.2mm) ;

straightening equipment:

three-roller straightening machine；

hydraulic straightening machine (multipoint straightening)

5. The second tempering removes the hard force, the temperature is about 480 °C, and Keep warm for 2 -2.5hours ; release 80% more or less

In the whole crafts process, there are 2 times remove hardening forces: the first remove hardening force in the heat treatment process, hardening force remove is about 80%; the second remove hardening force in the surface treatment process, hardening force remove is about 90%-95%. Therefore, the piston rod is not easily deformed during use or transportation.

CHEMICAL COMPOSITION