German mat'l code for bolts and gaskets 1

[JOHNPIA2]

I have a PV built in Germany in 1975; for bolt spec's they show 'DIN931, 24CrMo5'. What would be the equivalent ASME material?
For gasket, they show 'Jt300'only, and its thickness is 1mm.
What would be its m and y factors?
Thank you.

 

[TVP]

DIN 931 has been superceded by DIN EN 24014 which is identical to ISO 4014. In ISO 4014, ISO 898-1 is referenced for mechanical property requirements. With the alloy steel grade you provided, it is likely that this is supposed to be a Property Class 10.9 fastener.

Speaking of the steel alloy, are you sure it is "24CrMo5"? This grade is referenced in an Austrian standard, but the grade "25CrMo4" is a standard grade referenced across Europe (EN 10083-1). Not that it really matters, as they are almost identical. The composition of 24CrMo5 is as follows:

C = 0.20-0.28
Si = 0.40 max
Mn = 0.50-0.80
P = 0.030 max
S = 0.035 max
Cr = 0.90-1.20
Mo = 0.20-0.35

I am not familiar enough with ASME standards to recommend an equivalent product standard for fasteners. I can tell you that there are a number of ASTM standards for steel fasteners, and none of them has a direct equivalent for this steel composition, as a Cr-Mo alloy with only 0.25 nominal C is not a standard in the U.S. However, mechanical properties are the most important feature, not chemical composition, which means that an appropriate fastener standard like ASTM A 962M - 01 Standard Specification for Common Requirements for Steel Fasteners or Fastener Materials, or Both, Intended for Use at Any Temperature from Cryogenic to the Creep Range will provide the necessary details.

 

[ijzer]

There is no ASTM equivalent for 24CrMo5. 24CrMo5 bolts are much weaker than A 193 B7 ( although almost similar chemical composition).
It 300 is compressed asbestos. Not allowed anymore , but
m = 2.75 to 3.5
y = 3700 to 6500 psi

 

[JOHNPIA2]

Thank you both for your answers; I assumed an allow. bolt strees of 18800 psi, based on similar Cr-Mo ASME mat'l; the full-face gasket being 1mm thick, most probably is solid metal. It would make sense to me, when PV equipment is imported to North America, the owners should insist on ASTM equivalencies of materials, to avoid replacing them with the wrong type on repairs later.

 

[ijzer]

The assumed bolt stress is much to high. You don't mention the design temp.but based on ASME VIII-1 , 24CrMo5 would be
at Room temp. : 15950 psi
at 400 Deg. C : 11020 psi.

It300 is not solid metal but solid asbestos.