Steel coils

	Jiangyin Zhongjiang offers steel coil model ZJCB-014-3, which is coated with PE, SMP or PVDF. It comes in a thickness of 0.28 to 0.6mm.

Makers now employ more-efficient methods such as obtaining raw materials in bulk and preferring standard-width orders.

China suppliers of steel coils and sheets are taking a multipronged approach to coping with higher material costs. This comes amid plans of retaining, or even bringing down, prices in the months ahead.

Accounting for 70 to 80 percent of production outlay, steel reached $1,119 per ton in October 2008, up 25 percent from January. Companies did not raise quotes commensurately, however, for fear of losing orders. Many sacrificed profit margins to ensure that adjustments were limited to 20 percent.

To protect against further losses, cost-efficient material sourcing and manufacturing strategies are being tapped. One of these is procuring steel in bulk when costs are low to guard against fluctuation and gain more room to negotiate quotes. Large and some midsize enterprises source from reputable manufacturers at home and abroad, including Baosteel, Wuhan Iron and Steel, Jiangsu Shagang, South Korea’s POSCO and Nippon Steel of Japan. Smaller operations rely solely on the domestic market for their metal requirement.

During production, materials purchased at low and high rates are usually combined, enabling suppliers to keep a rein on spending, at least for the short term.

Optimizing material consumption to reduce wastage is another priority. Companies are concentrating on constructions that require minimal cutting and therefore generate only a small amount of metal scraps. Some of them are sticking to standard-width coils and sheets measuring 1 to 1.2m.

To ensure viability in the long run, manufacturers are also boosting output of models for residential and commercial building applications. Priced higher than designs adopted in factory workshops, these give suppliers a better chance at recovering margins and propping up sales.

Coils and sheets intended for use as structural and architectural elements are made of cold-rolled, and hot-dip galvanized or aluminum-zinc alloy steel.

The hot-dip coated line is often painted with PE, PU, PVDF, silicone-modified polyester, epoxy resin or plastisol before being shipped to downstream industries. The surface finish is usually in a solid color, with blue, green and white among the common options. A wood, marble, corrugated or weave pattern can also be replicated for aesthetic appeal, pushing prices beyond $1,400 per ton.

	Model SC-010 from Hangzhou Santiway is 0.2 to 0.6mm thick. The painted layer is 20µm.

Roughly one-fourth of China’s output is made of hot-dip galvanized steel.

Most models are plated with 100 to 200g of zinc per square meter. To meet performance requirements in outdoor applications, suppliers can go beyond this range, applying up to 350g and consequently raising prices by $7.50 to $42 per ton. Those operating on a medium and large scale often employ an air knife to check the consistency and thickness of plating layers. Surfaces can have a spangle or matte finish.

For prepainted designs targeting the building sector, PU and epoxy powder are commonly utilized as primer.

The top coat often comes in EP or PE, although SMP and PVDF can be adopted on request.

EP is preferred for its superior adhesion properties. Models with a PE finish, which protects against metal marking, marring and staining, can last five to eight years.

Providing greater pulverization and UV resistance, SMP is adopted to extend service life to between nine and 15 years.

PVDF models feature colorfast and all-weather coating, making them usable for up to 20 years.

Besides surface treatment materials, market positioning is determined by yield strength and international quality certification.

Low-end coils and sheets sustain less than 300MPa. Upscale designs reach or even exceed 500MPa, and conform to JIS, DIN, ASTM and EN standards.

Thickness is another differentiator, with thinner constructions fetching higher prices. Products measuring 5mm start at less than $1,100 and can go beyond $1,400.

Aluminum-zinc alloy models are popular particularly among China suppliers engaged in high-value production.

Compared with hot-dip galvanized coils and sheets, this category is 5 to 10 percent more expensive to manufacture because of additional coating-material requirements. Prices, as a result, are at least 25 percent higher.

Employing the hot-dip process, substrates are usually coated with 40 to 90g of aluminum and zinc per square meter. This makes models two to five times more corrosion-resistant than versions in pure zinc. They also offer greater protection against acidic reactions and water seepage. Further, the line fares better in terms of heat tolerance, with models capable of withstanding up to 315 C. For galvanized designs, the maximum temperature threshold is only 230 C.

Combined customs figures for nonalloy steel and iron sheets show that China exported $13.6 million worth of products in 2007. Close to matching last year’s sales, shipments during the first eight months of 2008 already amounted to $12.4 million.

The upward trend is driven by frequent price increases. In fact, based on the same trade statistics, the average value per kilogram has been rising steadily since January, reaching $1.10 in August.