The potential of plasma deposition techniques in the application field of forging processes

Abstract

High mechanical, chemical and thermal cyclic loads characterize the load regime of hot forging applications. Additionally these loads are acting simultaneously which leads to a failure of the form giving tool components after a short tool life. Accounting for about 70% of all causes, wear is the main reason for production downtimes. Other failure factors are thermal and mechanical cracks as well as plastic deformation as a result of the loss of hardness due to the high thermal charge. The caused production downtimes can be reduced by surface modifications of the tools. Different results of recent research works prove the high potential of newly developed PVD and PECVD coating systems regarding the reduction of die wear. CrVN coating systems developed by PVD coating equipment and boron containing multilayered PECVD coating systems were applied to forging dies. Basic investigations of the occurring wear mechanisms show the qualification of the coating systems which have to be adapted to the decisive process related loads and damages

Adapted surface properties of hot forging tools using plasma technology for an effective wear reduction

“…The investigation revealed a noticeable influence of the initial surface condition to their behavior on the ongoing forging process. An unstable core roughness throughout the forging cycles was determined as a crucial factor for the initiation of tremendous wear in hot forging operations [6]. Within the performed roughness measurements of the ring compression dies, a stable core roughness can only be achieved on smoother die surfaces.…”

“…Using automated handling systems, spray cooling and lubrication application is guaranteed to provide reproducible process conditions. A process cycle time of 7 s for each forged part was reached [6].…”

Increasing the Efficiency of Forging Operations Using Adjusted Tribological Surfaces Enhanced by Hard Coatings

“…Forging tools are subjected to high wear due to complex process conditions with high temperatures during the contact of die and billet as well as mechanical loads caused by high process forces. The resulting abridged service lifetime of the dies highly restricts the cost-effectiveness of the production process [5,8].…”

“…These treatments are applied to increase hardness as well as wear and corrosion resistance of forging tools at elevated temperatures [14][15][16]. Recent studies show the positive influence of plasma nitriding on the wear behavior of forging dies [5,8,13,18]. During these treatments nitrogen diffuses into the base material and the hardness in the edge zone increases.…”

The Use of 3D Scanning Methods to Evaluate the Hybrid Layer Used in Forging Tools in Order to Improve their Durability

“…This subject was also tested by authors in previous works [19], where they have found the advantage of using hybrid layers. Hybrid layers were successfully applied in bulk metal forming [20], diecasting [21] and hot forging [22]. Another technology which can significantly improve forging tool durability is pad welding [26].…”