Steel X2CrNiMo17-12-2 Testing for Uniaxial, Proportional and Non-Proportional Loads as Delivered and in the Annealed Condition

Abstract

The article presents the results of fatigue life and fractographic testing of steel X2CrNiMo17-12-2 exposed to proportional and non-proportional fatigue loads. The following load types were applied: tension-compressive strength, torsion, proportional combined/complex loads produced by tension-compressive strength and torsion as well as non-proportional combined load – by tension-compressive strength and torsion by the phase shift angle φ=90°. The paper analyses the effect of the load method on the fatigue life and fractography of fatigue fractures recorded, and especially the effect of non-proportional load.

Comparing Guidelines Concerning Construction of the S-N Curve within Limited Fatigue Life Range

“…Fatigue tests oriented on constructing the S-N curve within a limited fatigue life range can be performed based on guidelines given in [5,6,9,10,11], among other options. However, despite the fact that all these documents refer to the limited fatigue life range, each of them was prepared for an individually defined scope of applications and contains different guidelines.…”

“…According to the standard [11], tests oriented on determining the fatigue characteristic for a given reliability level, require 28 specimens as the minimum, while in preliminary tests 7 specimens are recommended as sufficient. The above guidelines do not define the number of the applied load levels, they only refer to the standard ASTM [6] which gives the relation for the replication percent: (1) where:…”

“…It is noteworthy that the minimal number of specimens recommended in the standard [11] is larger than that given in the document [6]. Numbers of specimens suggested in the ASTM standard are given in Tab.…”

“…On the other hand, the guidelines of the International Institute of Welding [5] suggest that the tests are to be performed for a minimum of 10 specimens, and for at least 2 levels of load within the range from 10 5 to 10 6 cycles. It is also noteworthy that the ISO standard [11] has the applicability range limited to determining fatigue properties of metal elements, while the ASTM document [6] refers generally to construction of the S-N curve when it can be estimated using linear regression for the probability not lower than 5%.…”

Analysis of Flatness Deviations for Austenitic Stainless Steel Workpieces after Efficient Surface Machining

“…The workpiece was a metal plate made from X2CrNiMo 17-12-2 austenitic stainless steel [16]- [17] and sized 150× 150×20 mm, whose characteristics are presented in Table 1. …”