are seamless pipes, chiefly in making hydraulic supports for coal mines, hydraulic cylinders and pistons for truck cranes and other purposes, among which hydraulic supports account for the maximum proportion. Supports are the supporting and protective facilities to prevent the ceiling from falling and to ensure the safety of those who work in the mine. Their cylinder and piston must be made with seamless steel tubes. the 34CrM04 steel plate required to have adequate safety in operation, high reliability, strength and tenacity so that even the pipe body cracks, it will not break into pieces. Such requirements are necessary because these pipes are used in damp environment underground, have to sustain very high pressure and load and tolerate constant corrosion and rusting.
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EN 10083-3/EN 10132-3
Number:1.7220
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Comparision of steel grades
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AISI
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4135
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DIN
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AFNOR
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34CD4
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BS
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708M32
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UNI
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35CrM04
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GB
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35CrM0
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SS
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2234
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SFS
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25CrM04
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GOST
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ISO
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34CrMo4
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Grade
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C
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P.max
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S.max
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Si.max
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Mn
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Cr
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Ni.
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Mo
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V
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34CrM04
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0.30-
0.37
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0.025
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0.035
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0.40
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0.60-
0.90
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0.90-
1.20
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-
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0.15-
0.30
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-
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Grade
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Thickness
(mm)
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Annealed+cold drawn(+A+C)
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Hardness HB maximun values
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34CrM04
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≥5≤10
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290
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>10≤16
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280
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>16≤40
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275
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>40≤100
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270
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Hydraulic support pipes
Source:
