英语翻译3Cr12 stainless steel which was developed with 0.03% C i

英语翻译
3Cr12 stainless steel which was developed with 0.03% C in the
late 1970s making use of the minimum chromium content required
to impart acceptable corrosion resistance is known as the
first generation of 12% Cr steels.Originally 3Cr12 is a trademark
and was not included in any international specifications.However
a 12% Cr steel developed from 3Cr12 has been designated DIN type
1.4003 and ASTM/ASME 41003.3Cr12 now appears in ASTM A240
as UNS S41003 and in Europe as Material Number 1.4003,although
the two specifications are not exactly the same.In particular,conformance
to S41003 does not require nickel as an alloying element,
although it is permitted,while conformance to 1.4003 does require
some nickel.In addition to the composition ranges of S41003 and
1.4003,some suppliers,but not all include a deliberate addition
of titanium.Because of the low alloying content,1.4003 alloys
may lie in the dual phase region consisting of a mixture of untransformed
delta ferrite,alpha ferrite which transformed from austenite
on cooling and martensite depending on the cooling rate,
consequently they are variously described as ‘‘ferritic” or ‘‘ferritic–
martensitic” 12% Cr stainless steel.In comparison to fully ferritic
grades like 409 and 430,3Cr12 is considered to have better
weldability and HAZ toughness in thick as well as thinner gauges,
and it is supplied in thicknesses up to 30 mm.Relatively low fracture
toughness of the HAZ has restricted their use where dynamic
loads are concerned.Although 5Cr12HT was developed later as a
second generation to give better toughness,weldability remained
limited due to the carbon content [5,11,16–28].