Commercial Testing of Forgings

Headnote

Commercial testing laboratories perform a variety of tests that help a forge verify the quality of its output and certify test results to the forge's customers. Tests performed include the use of chemical, mechanical, nondestructive and metallographic techniques.

Much has changed over the years. What has stayed constant, however, is that modern designers continue to push the envelope for new and exciting projects and designs. Forgers today manufacture a variety of products in a vast assortment of shapes and sizes from a variety of materials.

The many industries served by the forging industry include automotive, trucking, motorcycle, marine, commercial and military aerospace, off-highway, agricultural, power generation, defense and ordnance, valves and fittings, and industrial tools. The scope is wide and varied.

Consequently, the requirements called out for material properties are ever-changing. Today's forgings are regularly specified where strength, reliability and resistance to shock and fatigue are vital considerations. Unlike other manufacturing processes, forged materials offer a higher ability to meet varied performance temperatures. Thus, improved ductility and hardness, along with machinability, are added benefits.

Most of the producers of basic metal (i.e., steel, aluminum, copper, titanium and nickel) produce forged product. As a result, testing is often varied and unique to the material, application and specification called out.

Product Testing

Much has changed during the past 30 years, but the principal mechanical properties of interest to design engineers in the forging industry today are strength, ductility and hardness. The term testing of requirements focuses on mechanical testing and includes both destructive and nondestructive types. The types of testing will, in most cases, depend on customer requirements and prevailing specifications.

Testing specifications within the forging industry are generally governed by ASTM standards. In many cases, it is necessary for forging companies to turn to a laboratory that has the designated Nadcap and A2LA approvals.

Types of Testing

When it becomes necessary to verify material characteristics, mechanical properties or the existence of flaws, standard inspection methods are available. Many of the tests are classified as nondestructive because the sample is not harmed, but the rest are destructive tests. Some of the most commonly utilized test methods include chemical analysis, mechanical testing, nondestructive testing and metallography.

Chemical Analysis

The chemistry of the material used in forging usually...