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Comparison of chemical composition

I will explain by comparing the chemical composition of piano wire and hard steel wire.
How do the chemical compositions of piano wire and hard steel wire differ?

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Standards for chemical composition of piano wire and hard steel

First, I will explain the JIS standards that standardize the chemical composition of piano wire and hard steel wire.

The chemical composition of piano wire is standardized in "JIS G 3502 Piano Wire", and the chemical composition of hard steel wire is standardized in "JIS G 3506 Hard Steel Wire". These standards stipulate in detail the chemical composition of materials used to manufacture piano wires and hard steel wires.

A total of 18 types of piano wire materials and a total of 21 types of hard steel wire materials are standardized.

These materials undergo repeated processes such as heat treatment, pickling, and wire drawing to produce piano wires and hard steel wires of various wire diameters.

There are two similar standards, "JIS G 3522 Piano Wire" and "JIS G 3521 Hard Steel Wire", which standardize the types of piano wire and hard steel wire, tensile strength, tolerance of wire diameter, etc. increase. No chemical composition is mentioned.

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Chemical composition table of piano wire and hard steel wire

The chemical composition of typical piano wire rods and hard steel wire rods is as follows. (Unit: mass%)

Chemical composition	SWRS82A (piano wire)	SWRH82A (hard steel wire)
C (carbon, carbon)	0.80 to 0.85	0.79 to 0.86
Si (silicon silicon)	0.12 to 0.32	0.15 to 0.35
Mn (manganese)	0.30 to 0.60	0.30 to 0.60
P (Phosphorus)	0.025 or less	0.030 or less
S (Sulfur)	0.025 or less	0.030 or less
Cu (Copper)	0.20 or less	―

mass% is mass percent concentration. For example, 0.8 of C means 0.8g of C in 100g.

　"SWRS82A" is one of the 18 types of piano wire standard, and it is processed into piano wire type B (SWP-B).

Also, "SWRH82A" is one of 21 types of hard steel wire rods that can be processed into hard steel wire type C (SWC). SWC is a hard steel wire also called 80C (80 carbon).

　SWP-B is a representative steel grade for piano wire, and SWC is a representative steel grade for hard steel wire. Both can be said to be common materials with the highest distribution volume among steel types.

　Strictly speaking, it is a comparison of the chemical composition of the primary material used to manufacture the steel wire, but it can be regarded as a comparison of the chemical composition of the piano wire and hard steel wire, which are secondary processed products. It is always mentioned in the material report table.

　Looking at this table, it goes without saying that the control of the chemical composition of piano wire is stricter than that of hard steel wire. Conversely, however, some hard steel wires have the same chemical composition as piano wires.

　It just so happens that hard steel wire, which has the same chemical composition as piano wire, is of the same quality as piano wire, but that is not the case. There are other strict standards for piano wire that hard steel wire does not have. For example, there are standards for the depth of surface scratches and the depth of decarburized layers. These standards are not defined for hard steel wire.

Japanese Page ↓

>Chemical composition of spring materials

＞ About piano wire and hard steel wire

＞Chemical composition of piano wire

＞Chemical composition of hard steel wire

> JIS standards for spring materials

> Spring design "Five points for material selection"

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