What is cold rolled steel bar? Summary of standards for materials, sizes, tolerances, etc.

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Cold rolled steel bars are often used in mechanical design.

This section summarizes the specifications for cold rolled steel bars and how these specifications are organized.Centerless round bar　Please note that this is not the same as

What is Cold Rolled Steel Bar?

The appearance of cold rolled steel bars isThe material must be "straight, free of kinks, of correct cross-sectional shape, with smooth surfaces and free from any blemishes detrimental to its use."and therefore not a mechanical property.To reduce machining man-hoursCold rolled steel bars are often used in

In addition, since cold drawn steel bars are cold worked after the oxide film on the surface of the rolled material is removed, no oxide film is formed on the surface of the material. In general, "cold drawing" is considered to be a processing method with good dimensional accuracy and a clean surface.

The reason why cold drawn steel bars are cold drawn is because an oxide film is formed on the surface of the product when hot rolled or forged, and accuracy of shape and size cannot be expected. *Made by hot rollingFlat bar　The "A" is distinguished from the "B".

JIS Standards for Cold Rolled Steel Bars

The JIS standard for cold rolled steel bars is JIS G 3123, which applies to "cold rolled carbon and alloy steel bars with round, hexagonal, square or flat cross sections.

Types and Symbols of Cold Rolled Steel Bars

Cold rolled steel bars are broadly divided into the following two types

• carbon steelPolished steel bar
• Alloy SteelCold-rolled steel bars.

See the table below. For example, "S45C-D" in the commonly used brushed bar shape, "-D" means cold drawn. To be precise, the standard includes the heat treatment method and dimensional tolerances, such as "S45C-DQG7," but in many cases, "-D" is all that is required. The reasons for this areTo make machining easier and to reduce procurement costs for ease of distribution, rather than for the accuracy of the polished bar.This can be thought of as a

Thus, although most people are generally aware that cold drawing is the only way to produce cold drawn steel bars, it is possible to produce cold drawn steel bars by both grinding and cutting, to be precise.

Dimensions and tolerances of cold rolled steel bars

Cold-rolled steel barsStandard dimensionsis as follows

Dimensional Tolerance of Cold Rolled Steel Bars

Cold-rolled steel barsDimensional tolerances are based on tolerance class for shaft h according to JIS B 0401The company is doing so.

[Supplement 1
IT6 to IT9 (h*) is listed as.Information as reference IT6=h6, IT7=h7, IT8=h8, IT9=h9 with equivalent tolerancesThis means that

[Supplement 2
JIS B 0401 is an ISO code system for size tolerances

Surface roughness of cold drawn steel bars

Although there are differences in material, bar diameter, etc.Generally, the surface roughness of cold rolled steel bars is about Ra 0.4 to 0.9It is considered to be a

That's it.