Investigation of Forging Metal Specimens of Different Relative Reductions Using Ultrasonic Waves.

Ján Moravec,Peter Bury,František Černobila

doi:10.3390/ma14092406

Abstract

Forgings produced in industry are an irreplaceable basis for subsequent elaborating on machine tools. The quality of the semi-finished product produced by forging is a necessary prerequisite for ensuring the final quality of the final product because the forging can produce some defects. The presented paper is aimed at investigation of selected characteristics of forging steel specimens for various levels of their relative reduction. Ultrasound testing belongs to methods for investigation of structure changes, including defects. Experimental investigation, using both the attenuation and velocity measurements, verify that the reduction of specimens’ material can have an effect on the propagation of ultrasound waves passing through the specimen body. The procedure of steel samples forging corresponds accordingly to the process of their hardening. The increase of toughness after relative reduction of forging in the range of 10–50% is with highest probability caused by the strength matrices development due to the relatively important deformation hardening. It is evident that the deformation hardening is almost the same after every 10% addition of relative reduction. Experiments are supplemented by Barkhausen noise detection and metallographic characteristics of the samples. While differences between the Barkhausen noise values are in principle relatively small and significant differences are only in the values of the position of the envelope, there is maximum coincidence with ultrasonic investigation.

Highlights

IntroductionMetal beating is one of the basic forming processes, especially under dynamic loading.Hammering belongs to the field of forging and is the most common operation on impact machines (hammers, drop hammers, spindle presses, etc.)
Metal beating is one of the basic forming processes, especially under dynamic loading.Hammering belongs to the field of forging and is the most common operation on impact machines
The analysis of changes of mechanical properties in steel samples that undergo forging with respect to the original non-forging sample is presented

Summary

Introduction

Metal beating is one of the basic forming processes, especially under dynamic loading.Hammering belongs to the field of forging and is the most common operation on impact machines (hammers, drop hammers, spindle presses, etc.). Metal beating is one of the basic forming processes, especially under dynamic loading. In addition to its practical significance, beating is of fundamental importance for determining the mechanical properties under impact loading. The theory of plastic deformation propagation, taking into account the influence of the deformation rate, the thermal effect, the actual course of the load and the final dimensions, is still under investigation. Short samples can be used for beating on conventional machines. Various tests are applied to test forgings, such as checking the chemical composition of the material, checking the mechanical properties and structure of the forgings. These are commonly used tests in which forging errors can be detected

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Conclusion