DIN 17240 Grade 21CrMoV57 / 1.7709

21CrMoV57 / 1.7709

Chemical Composition

Chemical composition of heat resisting and highly heat resisting materials for bolts and nuts (ladle analysis)

Material Chemical composition in % by wt.
Code number Material number C Si Mn I' S Al B Cr Mo Ni Ti V Others
maximum
Standard grades
 1) Only usable for nuts.
  2) Instead of bolts and nuts of this steel, it is possible for a transitional period to use also bolts and nuts of steels 24 CrMoV 5 5 (material number 1.7733) and 21 CrMoV 5 11 (material number 1.8070) (see Explanations). In special cases, it is possible also to use steel 21 CrMoNiV 4 7 (material number 1.6981) instead of this material
  3) For this alloy, in all cases the values given in the latest issue of DIN 17 742 apply.
 4) Lower silicon contents may be agreed at the time of ordering, in which case any resulting changes in the guaranteed properties must be taken into account.

Mechanical Properties

Guaranteed values for mechanical properties at room temperature of heat resisting and highly heat resisting materials for bolts and nuts (applies to longitudinal specimens)

Material1) Density
at 20 °C
Coefficient of thermal expansion between 20 °C and
10 -6 K -1		 (Mean)
thermal conductivity 1)
(Mean) specific
heat capacity 1)
Code number Material number kg/dm3 100 °C 200 °C 300 DC 400 °C 500 °C 600 °C 700 °C 800 °C at °C W/K+m at °C J/Kg+K
21CrMoV57 1.7709 V 250 550 500 480 460 441 412 372 334 275
  1) Only usable for nuts.
  2) See also Tables 3 and 8.
  3) For acceptance testings, agreement can be made as to which of the two shapes of specimen quoted is to be used. If the values obtained for absorbed energy are below the minimum required values for ISO V-notch specimens, proceed as if the proof of absorbed energy were required on DVM specimens.
  4) In the case of nuts, the normal upper limit of temperature of use in continuous operation can be 50 00 higher.
 5) Because of its subsequent working by cold-forming, steel Cq35 is normally supplied in the "spheroidized" (GKZ) condition.
 6) The upper limit of the tensile strength range must not be exceeded; values slightly below the lower limit of the tensile strength range are permissible provided the minimum value for the yield point is reached.
 7) The values given are provisional values that will have to be checked.