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
1.Quenching with fire about 860 °C, placed in furnace box
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
| Material | C% | Mn% | Si% | S% | P% | V% | Cr% |
| Ck45 | 0.42-0.50 | 0.50-0.80 | 0.04 | 0.035 | 0.035 | | |
| ST52 | 0.22 | 1.6 | 0.55 | 0.035 | 0.04 | | |
| 20MnV6 | 0.16-0.22 | 1.30-1.70 | 0.10-0.50 | 0.035 | 0.035 | 0.10-0.20 | |
| 42CrMo4 | 0.38-0.45 | 0.60-0.90 | 0.15-0.40 | 0.03 | 0.03 | | 0.90-1.20 |
| 40Cr | 0.37-0.45 | 0.50-0.80 | 0.17-0.37 | | | | 0.80-1.10 |
MECHANCIAL PROPERTIES |
| Material | T.S N/MM2 | Y.S N/MM2 | E%(MIN) | CHARPY | CONDITION | | CK45 | 610 | 355 | 15 | >41J | NORMALIZE | | CK45 | 800 | 630 | 20 | >41J | Q + T | | ST52 | 500 | 355 | 22 | | NORMALIZE | | 20MnV6 | 750 | 590 | 12 | >40J | NORMALIZE | | 42CrMo4 | 980 | 850 | 14 | >47J | Q + T | | 40Cr | 1000 | 800 | 10 | | Q + T |
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