Cold-rolled products per GOST: a simple guide to choosing quality steel strip

To avoid disappointment in purchased material and manufacture a product of the highest quality, one must choose cold-rolled strip conforming to GOST 21996-76. One of its main criteria is high accuracy of geometric dimensions. This makes it possible to manufacture parts and structures fully matching technical specifications, and also to use material economically, minimizing waste.

In addition, cold-rolled metals have excellent mechanical properties, in particular high strength and resistance to wear and corrosion. But let us consider how sheet material conforming to the established state standard should look.

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GOST 21996-76: what characteristics it regulates

The first thing the GOST speaks of is metal classification and assortment. Cold-rolled strip is divided by the following features:

• Strength — may be of the first, second, or third group. Marked 1P, 2P, and 3P respectively. Indicators are temporary resistance or hardness (only one of these parameters is controlled).
• Edge type — may be processed (D) or trimmed. In the first case the edge must be blunt; in the second, minimal burrs and irregularities are allowed.
• Production accuracy — normal, elevated, and high. Moreover it may be regulated both by width (PSh and VSh) and by thickness (PT and VT). The GOST sets allowable dimensional deviations for each strip type according to its thickness and width.
• Surface type: bright tempered — must have a color from light to dark gray; bright tempered with an oxide film of iridescent colors — temper colors may be from pale yellow to saturated blue (marking — Ts); dark — may be any color, and also covered with an oxide film or a grease layer (denoted by the letter Ch); colorized — may have any shade from dark blue to light yellow, including several at once in one coil (marking — K); polished — has a shiny surface (marked with the letter S). Overall dimensions — at sheet width up to 40 mm its thickness may start from 0.05 mm; at width from 45 mm thickness must be at least 0.1 mm.

• Overall dimensions — at sheet width up to 40 mm its thickness may start from 0.05 mm; at width from 45 mm thickness must be at least 0.1 mm.

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Technical requirements for cold-rolled strip

GOST 21996 approves steel grades that may be used for cold rolling, as well as a number of technical characteristics that the finished product must meet. Including:

• Vickers hardness: for the first strength group — 375–485 N, for the second — 486–600 N, for the third — over 600 N;
• temporary resistance: for the first — 130–160 kgf/mm², for the second — 161–190 kgf/mm², for the third — over 190 kgf/mm²;
• number of bends: the minimum allowable value depends not only on the material strength class but also on the steel grade;
• strip surface quality: there must be no delamination, rust, cavities, scratches, roll marks, and a number of other damages.

GOST 21996-76 also regulates thickness and mass of cold-rolled strip coils, marking, packaging, transportation and storage rules, technical control norms for accepting finished products, and product test methods.

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How to choose cold-rolled strip

Often metallurgical enterprises release cold-rolled products not to GOST but to their own TU (technical specifications). Meanwhile visually such material may fully match the established standard, but in service it may present unexpected unpleasant surprises. If at your production you strictly monitor quality of products released, we recommend reading technical documentation before buying cold-rolled metal, and also checking conformity of the metal to stated characteristics (geometric dimensions, surface quality, mechanical properties).

Another option is to choose a reliable supplier that releases cold-rolled strip to GOST and can provide corresponding certificates. One such is Petersburg Plant of Precision Alloys. The enterprise has the necessary production capacity and its own quality control laboratory with modern high-precision equipment. All this makes it possible to release cold-rolled products in full conformity with GOST 21996, and also to produce products to individual orders (with any tolerances and from any steel grades). If you want to order cold-rolled strip, call us or leave a request; we will contact you promptly.