Materials In Automotive Industry Research Articles

Adhesive Bond Discrepancies Identification with Hybrid Dynamic Parameter Method

With the implementation of crash-toughened adhesives in automotive industry, adhesive bonding has become one effective joining technology instead of resistance spot welding especially for AHSS materials because of its better fatigue performance and greater flexibility. However, while chisel test has been widely used for resistance weld inspection, no practical inspection method is available for adhesive bond discrepancies identification. The inspection method we need for use in a high-volume, low-cost production environment should be fast, convenient, nondestructive, cost-effective, and able to effectively assure some minimum acceptable level of joint quality. The method we finally conducted was based on the weld-bonding process of different adhesive bonding joints by acquiring and analyzing the dynamic welding parameters’ signal curves such as the electrode displacement and dynamic resistance from different sensors installed onto the welding gun. Based on the integrated inspection system, lots of experiments and analysis showed that this inspection method is basically feasible, that is, it could identify different adhesive bond discrepancies qualitatively and accurately. Especially, the on-line inspection is conducted before the complete curing of joints in paint shop. If the inspection results are nonideal and some discrepancies are detected, the further repairing work is much easier and cost-effective. So the inspection method has a good potential especially applied in production line. The findings in this study provide the guidelines for using adhesive bonding AHSS materials in automotive industry.

New Materials for Auto-Body Lightweight Applications

The main developing trend of automobile industry is promoting performance, lowering fuel consumption, reducing hazard gas emission and promising safety of driving. The automobile lightweight technology has attracted more and more attention recently. Furthermore, auto-body lightweight is very important to automobile lightweight, and new material has become an important technical support for auto-body lightweight. In this paper, the currently used materials in automotive industry were reviewed, and the focus has been put on the application of new lightweight materials in auto-body and the trend of development.

Solidification studies on sand cast Al 6061–SiC p composites

Most of the automotive components are cast and their performance depends very much on the solidification phenomenon. Solidification is primarily a process of achieving solid crystals from the liquid melt by promoting zones possessing very high cooling rates to ensure super cooling of the melt. Till date enormous data is available as regards the solidification behaviour of popular light alloys such as Al 6061 and A 356 with regard to the casting process, mould materials used and other important processing parameters. Effect of chills on the solidification behaviour of the above materials has also been reported suggesting chills to be an important promoter of directional solidification. Directional solidification results in minimized solidification defects. However, there is a lack of information regarding the effect of chills on solidification behaviour of aluminium based metal matrix composites which are currently the most potential candidate materials in automotive industries as a replacement for conventional light alloys. In the light of the above, this work is aimed at experimentally studying the solidification behaviour of Al 6061–SiC p castings in sand mould using copper and mild steel chills. Further, commercially available finite element analysis (FEA) software has been used to predict the cooling curves with and without the use of chills for the developed composite. The experimental and predicted cooling rates of the developed composites are not in good agreement. Use of copper chills resulted in promoting higher cooling rates during the solidification of developed composites.

A dipping E-coating for Mg alloys

Mg alloys are becoming more and more important structural materials in automotive industry. However, most commercial Mg alloys require coating protection because of their poor corrosion performance. In this paper, a self-deposited “electroless” E-coating process for Mg alloys is presented. By utilizing the unique electrochemistry of Mg, a thin film is rapidly formed on the surface of Mg alloys by simply dipping in an E-coating bath. The new developed dipping technique does not need a current or potential that is essentially required in a normal E-coating process. It is believed that the surface alkalization effect of Mg is responsible for the deposition of the “electroless” E-coating pre-film while the diffusion of hydroxyls in the porous film is governing the film growth. The rapidly formed pre-film can offer sufficient corrosion protection for Mg alloys in a chloride-containing environment or a phosphating bath in a paint line. The stability of the film can be significantly improved by the curing process. It is found that the coating performance is influenced by the type of Mg alloy and the surface pretreatment. The dipping coating can also act as a base for further powder-coating.

Semi-solid moulding: Competition to cast and machine from forging in making automotive complex components

The very latest technique for impeller manufacture is called semi-solid moulding (SSM). Cummins Turbo Technologies Limited, together with Aluminum Complex Components Inc, developed SSM compressor wheels as a way of achieving cost and durability performance somewhere between that of cast and machined from solid (MFS) aluminium alloy wheels. Experimental results show SSM material has a superior microstructure and mechanical properties over cast and comparable to MFS materials. Component testing including durability testing, using accelerated speed cycle tests, proves SSM compressor wheels emerge as being significantly more durable than cast equivalents and approaching that of MFS impellers. Further challenges for semi-solid processing in manufacture of other complex components and other materials in automotive industry in terms of both cost and durability are also discussed.

Microstructural and Mechanical Characterization of Gray Cast Iron and AlSi Alloy after Laser Beam Hardening

A localized source of heat, such as that of laser beam, can provide a convenient means of producing a surface layer of altered microstructure. By using surface hardening treatment, wear resistance can be increased. Experiments were performed using a Nd:YAG pulsed laser under different processing conditions. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray mapping (SEM) were employed to observe the effect of laser melting treatment on the microstructural properties of the samples. Depending on the selected laser treatment working conditions, different microstructures characteristics of surface melting can be achieved in the treated zone. Higher microhardness values were found at the treated area showing a superficial hardening of the sample and, consequently, an improvement of the wear resistance of these automotive alloys. The aim of this work is to find the optimal process parameters and to evaluate the characteristics of the laser superficial hardening (LSH) in a pearlitic gray iron and Al-Si alloy used in an automobile industry (bearing and piston materials in automotive industry).

自動車産業と新素材開発 テクノアメニティを求めて

自動車産業と新素材開発 テクノアメニティを求めて