Manufacturing of High-Performance Bi-Metal Bevel Gears by Combined Deposition Welding and Forging

Abstract

The present paper describes a new method concerning the production of hybrid bevel gears using the Tailored Forming technology. The main idea of the Tailored Forming involves the creation of bi-metal workpieces using a joining process prior to the forming step and targeted treatment of the resulting joint by thermo-mechanical processing during the subsequent forming at elevated temperatures. This improves the mechanical and geometrical properties of the joining zone. The aim is to produce components with a hybrid material system, where the high-quality and expensive material is located in highly stressed areas only. When used appropriately, it is possible to reduce costs by using fewer high-performance materials than in a component made of a single material. There is also the opportunity to significantly increase performance by combining special load-tailored high-performance materials. The core of the technology consists in the material-locking coating of semi-finished parts by means of plasma-transferred-arc welding (PTA) and subsequent forming. In the presented investigations, steel cylinders made of C22.8 are first coated with the higher-quality heat-treatable steel 41Cr4 using PTA-welding and then hot-formed in a forging process. It could be shown that the applied coating can be formed successfully by hot forging processes without suffering any damage or defects and that the previous weld structure is completely transformed into a homogeneous forming-typical structure. Thus, negative thermal influences of the welding process on the microstructure are completely neutralized.

Review of recent developments in manufacturing lightweight multi-metal gears

“…The use of forging for bi-metal gear production dates back to as early as the 1970s [132]. Studies by Politis et al [118] and Chugreeva et al [38] have demonstrated the production of bi-metal spur gears and bevel gears respectively through forging, with Chavdar et al [32] investigating the principle of hydroforging. In addition, Meißner et al [97] analysed the performance of helical gears manufactured from multi-component forging and layered sheet stapling.…”

“…Several research works have proposed variants of welding to join dissimilar metals prior to forging. Welding of dissimilar metals may be achieved by metal inert gas welding, submerged arc deposition, plasma-transferred arc [51], c Micrograph of the bond zone before forming, d Micrograph of the bond zone after forming [38] (PTA), laser deposition welding and electro-slag-welding [6]. Chugreeva et al [38] utilised deposition welding to produce a preform for a forged bevel gear manufactured from a cylindrical base material coated with a dissimilar metallic layer.…”

Investigation of the influence of the forming process and finishing processes on the properties of the surface and subsurface of hybrid components

“…Behrens et al and Chugreeva et al manufactured hybrid bevel gears using a Tailored Forming process chain [3,4]. Shafts of low alloyed steel C22.8 with a protective cladding of heat treatable steel 41Cr4 were manufactured using a plasma transferred arc (PTA) welding process.…”

Skew Rolling of Bimetallic Rods

“…One example are axle shafts, in which the hub is fastened to the axle shaft in the process of frictional butt-welding [18,19]. Studies have also been carried out on plastic forming of two materials during which they are welded to yield a monolithic part characterized by unique physico-chemical properties [20][21][22][23]. It should be noted, however, that in many cases, the process of joining two different materials is relatively expensive and complicated [24,25], and does not guarantee the formation of a permanent joint.…”