GL船级社型钢规范.pdf

A Steel Plales, Strips, Sections and Bars
Chapter 2
GL2005
Page 1-1
ton
Steel Plates, Strips, Sections and Bars
A. Genera Rulcs
2 If the matcrial is suitable, products may also
thcrmo-mcchanically rolled condition (scc 4.3), pro-
vided thal the processes have been checked and ap-
1.1 General rules to be applied in the manufac- proved by (il. on the mamufacturers premises
ture and testing of hot-rolled plates, strips, sections
(including hollow scctions), rods and bars are con
Dcfinitions
tained In
Ihe processes mentioned in 4.2 are defined as follows:
Hot-rolled round bars intended for the manu
facture of shafts, tie rods and bolts are subiect to
lising rolling
ction3、B.
Normalising rolling (controlled rolling )is a rolling
process involving linal forming ln a specilic tempera-
conforming to national or international standards may
ture range which results in a material condition
be used, provided thal they satisfy the minimum re
equivalent to that achieved by normalising treatment
quircmcnts of these Rulcs
thus the desired values of the mechanical properties
re preserved even after an additional normalising
trcatmcnt
Rcquircmcnts to he mct by manufacturers
Manu laclurers wishing to supply products in accor
supplied in this condition are designated by
dance with these Rules must fulfil the requirements sel
NV
out in Chaptcr I-principles and Test Proccdurcs
Section 1, C, and must demonstrate this to GL prior to
43. 2 hermo-mechanical rolling
commencing supplies. In addition, an approval test on
products selected for the purpose is normally require
Thermo-mechanical rolling is a rolling
This may be dispensed with in the case o[ steels con-
orating careful monitoring of both the rolling tem-
forming to recognized standards, the suitability of
perature and also the reduction per pass. The greater
which Is considered to have been proved by practice
proportion of reductions pcr pass is gcncrally carric
out close to the upper transformation temperature A,3
construction of cargo handling and processing equip
where rolling in (he two-phase temperature range may
ment On gas tankers
incorporated. Unlike normalising rolling, the prop
crtics produccd by thermo-mcchanical rolling cannot
be reproduced by subsequent normalising or other heal
teelmaking process
treatments
3.1 The steels are to be manufactured by the Products supplied In this condition are designated by
basic oxygen process, the clectric furnace process or
the code TM
by other methods approved by GL. On request, GL
shall be informed of the steelmaking process used
Acceerated coohng followng MI
place if this process has been approved by (IT. The
steels may be cast in ingots (static cast
ame applies to tempering treatments Lollowing TM
Ing)or continuously
rolling
Spccial casting processes require initial appraisal by
Note on H steel
subseguent, continuous heating above 580 oc as
Condition of supply and heat treatment
well as significant long holding times at lower tem
peratures may impair the strength properties. The
All products are to be supplied in the heat
anufacturer must be consulted where there is a re-
trcatcd con