This Standard specifies the low-alloyed steels for machine structural use (hereafter
referred to as "steels"), which are manufactured by hot forming such as hot rolling
and hot forging. Steels are normally used after further forming such as forging and
cutting and heat treatment or nitriding.
NOTE 1 Depending on the thickness, steel plates and steel strip may include
those subjected to cold rolling in addition to those manufactured by
hot forming.
NOTE 2 The International Standards corresponding to this Standard are as
follows.
ISO 683-1 : 1987 Heat-treatable steels, alloy steels and free-cutting
steels--Part 1: Direct-hardening unalloyed and low-alloyed wrought
steel in form of different black products
ISO 683-10 : 1987 Heat-treatable steels, alloy steels and free-cutting
steels--Part 10: Wrought nitriding steels
ISO 683-11 : 1987 Heat-treatable steels, alloy steels and free-cutting
steels Part 11: Wrought case-hardening steels (Overall evaluation :
MOD)
In addition, symbols which denote the degree of correspondence in
the contents between the relevant International Standards and JIS
are IDT (identical), MOD (modified), and NEQ (not equivalent) ac-
cording to ISO/IEC Guide 21.