Collaboration Optimizes Con- Rod Manufacturing

June 1, 2006
Development work by Corus and a British forger leads to significant weight reduction opportunities and improved machining of connecting rods.

Corus Engineering Steels, based in Rotherham, England, is working closely with Smethwick Drop Forge (SDF), the U.K.'s leading forger of connecting rods for passenger and commercial vehicles, to help optimize the design and manufacture of existing con-rod designs.

SDF approached Corus for help in developing its con rods to meet its customers' on-going need to reduce component weight, to improve component fatigue performance, and to reduce machining to take costs out of the manufacturing process on current production components.

The collaboration between SDF and Corus tapped into the steelmaker's extensive expertise in computer modeling techniques, and its in-depth knowledge of materials to evaluate the benefits of using different grades of steel to meet these objectives.

For one customer in particular, SDF wanted to explore several options for optimizing an existing con-rod design. The collaboration first investigated what could be achieved by using traditional air-cooled steels. Corus developed an enhanced machining grade, which has allowed the con rod to be made from higher-strength material, resulting in improved component performance, but, importantly, without sacrificing throughput on the machining line.

Another critical aspect of the evaluation project was looking at the benefits of switching to fracture-split steels. Fracture-split steels allow the rod and cap to be separated along a pre-determined fracture line. This ensures a perfect fit between the two halves and results in engine-performance benefits, dramatically reducing the amount of machining the con rod needs, therefore taking cost out of the production process.

The latest steel developments from Corus exhibit increased durability and improved machining compared to the industry standard C70S6 material.

As part of the development work, engineers from Corus Automotive, based in Coventry, England, used computer simulation techniques to evaluate the fatigue performance of each new material variant and to identify potential mass savings. Corus Automotive is an innovator for vehicle engineering solutions that use the latest thinking in materials and manufacturing technologies, including advanced CAE simulation techniques.

The results demonstrated that SDF could reduce component weight by up to 15%, a benefit they could pass on to their customers to help them improve engine efficiency and meet stringent environmental legislation.

Commenting on the collaboration, Mark Adams, managing director of SDF, stated: "By partnering with Corus and utilizing their material knowledge and expertise in computer simulation techniques, we have been able to carry out many iterations in a short space of time to determine optimum con-rod design for our customers."

Adams continues: "Importantly, we have been able to enhance our credibility with our customers by demonstrating knowledge of a full engineering assessment, and as a result we have been able to offer a component with reduced weight, improved performance and reduced manufacturing costs."

The next stage of collaboration between Corus and SDF is already under way with the inclusion of forging design details into a knowledge-based engineering package, adding further to the comprehensive design and assessment capability SDF is able to offer its customers now.

Corus Engineering Steels is a unit of the steelmaker's long-products division, and supplies billets, bars, and bright bars to manufacturers of precision components for aerospace, automotive, energy-related, and specially engineers mechanical applications. Its products are offered in hundreds of carbon, alloy, and stainless specifications, in a comprehensive range of sizes, shapes and finished conditions. It also produces remelted steels for aerospace and high-performance engineering.

Smethwick Drop Forge Ltd., at Kidderminster, Worcestershire, is one of England's longest-established forging operations, and one of the leading suppliers of connecting rods to the automaking sector. The operation was acquired by SDF from United Engineering Forgings in 2001, in the course of that company's bankruptcy liquidation.