Monotonic and Cyclic Behavior of DIN 34CrNiMo6 Tempered Alloy Steel

Ricardo Branco,José Costa,Fernando Antunes,Sandra Perdigão

doi:10.3390/met6050098

Ricardo Branco, José Costa + Show 2 more

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https://doi.org/10.3390/met6050098

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Journal: Metals	Publication Date: Apr 26, 2016
Citations: 38	License type: CC BY 4.0

Affiliation: Polytechnic Institute of Coimbra, University of Coimbra

Abstract

This paper aims at studying the monotonic and cyclic plastic deformation behavior of DIN 34CrNiMo6 high strength steel. Monotonic and low-cycle fatigue tests are conducted in ambient air, at room temperature, using standard 8-mm diameter specimens. The former tests are carried out under position control with constant displacement rate. The latter are performed under fully-reversed strain-controlled conditions, using the single-step test method, with strain amplitudes lying between ±0.4% and ±2.0%. After the tests, the fracture surfaces are examined by scanning electron microscopy in order to characterize the surface morphologies and identify the main failure mechanisms. Regardless of the strain amplitude, a softening behavior was observed throughout the entire life. Total strain energy density, defined as the sum of both tensile elastic and plastic strain energies, was revealed to be an adequate fatigue damage parameter for short and long lives.

Highlights

DIN 34CrNiMo6 high-strength steel is a martensitic steel, and, within the group of advanced high-strength steels, provides the highest yield strength and the ultimate tensile strength
Martensitic steels, generally speaking, are characterized by a martensitic matrix containing small amounts of ferrite and or bainite. This microstructure is the result of a rapid quenching, which transforms most of the austenite into martensite
This paper aims the systematic characterization of monotonic and cyclic behavior of DIN 34CrNiMo6

Summary

Introduction

DIN 34CrNiMo6 high-strength steel is a martensitic steel, and, within the group of advanced high-strength steels, provides the highest yield strength and the ultimate tensile strength. The main process responsible for the strengthening in this steel is the precipitation of a fine dispersion of alloy carbides during tempering This steel, in particular, is a very versatile engineering material employed in the manufacture of a wide range of critical mechanical components, such as axles, shafts, crankshafts, connecting rods, valves, propeller hubs, gears, couplings, torsion bars, aircraft components, and heavy duty parts of rock drills, among others. It advantageously combines high ductility, deep hardenability, toughness, and strength

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