WYJ046-2006                        2.25Cr-1Mo-0.25V

1, applicable scope

The technology conditions apply to hydrogenation equipment in 2.25 Cr-1 Mo-0.25 V thick plate production and inspection.

2, the steel plate size and shape, weight and deviation should be allowed to meet ASME SA20/20 M of the provisions of the standard.

3, technical requirements

3.1 chemical composition

The chemical composition of the steel plate should be in accordance with table 1.

Wt%     table 1

note：“*”Only for record, do not make judgement basis。

Tempering sensitivity modulus should meet the following embrittlement requirements:

J=(Si+Mn)(P+Sn)×10⁴≤100

(P+Sn)≤0.014％

Formulaof element to the percentagereplaced

X=(10P+5Sb+4Sn+As) ×10^-2≤15ppm

Formula of element to the ppm  replaced

3.2 delivery status: the steel plate to normalized (in order to ensure that the microstructure of frequency is 90% bainite speed water quenching cooling) + tempering state delivery.

3.3 all steel plate with the inspection to try to simulate the billet after welding heat treatment, process system for:

The biggest simulation welding heat treatment：Max.PWHT:705⁺¹⁵℃×26～28h

Minimum simulation welding heat treatment：Min.PWHT:705_-15℃×6～8h

3.4 grain degrees and nonmetallic sundries

Metallographic organization has 90% of tempering bainite, not coarse grain degrees in grade 5; The steel plate non-metal inclusions of sulfide (class A), alumina class (B class), Portland class (C) and ball oxide class (D class), single grain globular class (DS kind) are not more than 1.5 magnitude, and should meet A + C ≤2.0, B + D + DS≤2.0, the total ≤4.0.

3.5 mechanical properties

The mechanical properties of the steel plate should comply with the table 2 and provisions (sample for simulation of heat treatment after welding state) :

Table 2

Note ：Record every sample of impact lateral expansion value and the percentage of ductile fracture。When impact energy a value less than the lowest, allow the A370 standardreinspect。