Automotive fasteners

	Jia-Chyi of Taiwan offers cold-forged screws for passenger cars and ATVs. These come in 3 to 16mm diameters.

Regulatory pressures are pushing makers to enhance corrosion resistance through chrome-free surface finishes.

Mainland China and Taiwan suppliers of automotive fasteners are exploring nontoxic and corrosion-resistant surface treatments to meet environment-protection standards in developed markets.

Many of them are seeking substitutes to hexavalent chromium, a traditional coating material. The use of this has been restricted in the EU’s RoHS and WEEE directives due to its harmful environmental and health effects.

Currently, trivalent chromium is the industry’s preferred alternative. A number of companies, however, anticipate that the compound will also be banned in coming years and therefore see it only as a temporary solution.

So to ensure long-term competitiveness in Europe and the US, these suppliers have started shifting to chrome-free options.

Those in the mainland are tapping organic and inorganic substances, including silicates, and epoxy and acrylic resins. As passivation agents, the materials form a hard and nonreactive film on top of zinc-plated surfaces, inhibiting premature corrosion.

In Taiwan, government and academic institutions are supporting this “green” initiative primarily through technology transfers. Among the options gaining ground there are silicon dioxide and epoxy powder. Besides being ecologically safe, the latter protects against chemical deterioration.

Companies in the island are also exercising greater flexibility in catering to customers’ surface treatment specifications.

Most are capable of offering steel fasteners in yellow or white zinc-plated, black or gray phosphate and hot-dip galvanized finishes. Titanium models can be anodized in different colors.

With R&D geared toward surface treatments, mainland suppliers are opting to keep their designs traditional. Models are usually produced in standard specifications and for basic applications.

Ruian Dongfang Auto Parts Co. Ltd focuses on wheel assembly in its latest series of bolts and nuts, which are made of 40Cr and A3 steel, respectively.

Model YJ-1211 from Ningbo Yinzhou Yingjie Automobile Fittings Fty is suitable for flexible valve extensions. It can come in mild steel, although the company also adopts brass and bronze.

Ningbo Motor Industrial Co. Ltd has released cone seat bolts with M12x1.25, M12x1.5 or M14x1.5 threads and 17 or 19mm heads.

Jinan Flybo Motor Co. Ltd produces fasteners mostly for trucks and cars.

To counter intense competition from the mainland, Taiwan suppliers are stepping up the manufacture of application-specific fasteners.

At Fwu Kuang Enterprise Co. Ltd, the emphasis is on specialized designs for cars, jeeps, RVs and trucks from Japan, South Korea, the US and Europe. Among these are welded bolts and studs that can be mounted on bumpers and grilles, and ball-tip screws compatible with transmission parts. Engine mount, and clutch, brake and exhaust system fasteners are available as well.

Jia-Chyi Industry Co. Ltd also manufactures engineered steel screws, bolts, nuts and studs for cars, motorcycles and scooters. Models undergo cold forging and CNC machining. Surface treatment options include gray or black phosphate, and white or yellow zinc plating.

Chief Forge Co. Ltd concentrates on high-end wheel fasteners that can be used with Japan-brand trucks and trailers, including Hino, Isuzu, Mazda, Toyota, Mitsubishi, Nissan and Daihatsu. Pieces are heat-treated to 31 to 34HRC and have a length tolerance of 1 to 3mm.

New bolts and nuts from Matrix Metals Corp. are designed for the wheel hubs of European, and US-, Japan- and South Korea-made cars, jeeps and RVs.