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Changes related to materials
● Increase the requirements for material grade. For example, valve stem F6a-II increases the requirements for the chemical composition of materials for pressure-bearing parts and pressure-control parts.
● For the control of sulfur and phosphorus content of weld end materials, higher requirements are put forward:
→● Sulfur content not to exceed 0.020%;
→● The sulfur content shall not exceed 0.020% and the phosphorus content shall not exceed 0.025%.
The old version are 0.035%.
● Toughness test requirements. For duplex stainless steel to increase the impact toughness requirements:
→ Average value of three specimens: minimum 45J;
→ Individual specimen value not less than 35J;
→● The impact test temperature shall be -46℃.
● Compatibility of rubber materials
For valves greater than or equal to Class 600, explosion-proof sealing materials shall be selected under gaseous working conditions with rapid pressure reduction.
● Materials for acidic media for pressure-bearing and pressure-control parts shall be selected in accordance with NACE MR0175 or in accordance with MR 0103, and the buyer shall specify the standard to be used (which is different from the original standard's specification to meet ISO 15156)
● New: Tensile test is taken on the test piece (TC) after final heat treatment. Room temperature tensile tests are in accordance with ASTM A370 or ISO 6892-1. At least one tensile test is made and the yield strength is determined using 0.2% residual deformation.
Forging materials are no longer mentioned as requiring grain size
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Changes related to welding
1, the welding material should be in line with AWS and the manufacturer's specifications, the selection of low-hydrogen type materials (including wire, flux) and according to the manufacturer's recommended requirements for storage and use, in order to maintain the low hydrogen properties of the material.
2. Requirements for surfacing or cladding welding of cemented carbide, the chemical composition of the thickness of the surfacing or cladding shall meet the following conditions:
Class Fe10 : Iron mass content of up to 10%;
Class Fe 5: iron mass content of up to 5% when the buyer specifies
Surfacing thickness requirements: minimum thickness of 3.0mm, should be surfaced two layers;
3. Welding repair of defects in forgings or plates is not permitted, unless otherwise agreed.
Weld patching of castings may be utilized to correct machining errors. After repair should be according to the standard post-weld heat treatment PMHT
4, new filler welding requirements, filler welding to be in accordance with 5.1 design requirements, including wall thickness considerations. Patch welding should be in accordance with the standard post-weld heat treatment PMHT.
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quality control related changes
1,Pressure measuring instruments
Pressure measurement should be carried out between 20% and 80% of the full scale of the manometer, the old version was: 25% to 75%
New pressure recording device does not belong to 8.2.3.1, for example: pressure recorder
2. Calibration cycle
Add the establishment of the calibration cycle of pressure instrumentation
The calibration cycle is a maximum of three months:
The calibration period may be shortened or lengthened according to the provisions prepared by the manufacturer on the adjustment of the period and the evaluation of the calibration history, and the maximum calibration period shall not exceed one year.
3. Heat treatment equipment calibration
Consistent with section 6.1
Heat treatment equipment at least once a year (within 12 months) calibration and measurement
4, in accordance with ASNT SNT-TC-1A or ISO9712 as the basis for assessment, no longer recognized EN473 standard
5, welding inspector
For the visual inspection of welding operations personnel according to one of the following assessment and confirmation:
AWS QC1 or equivalent certified welding inspectors;
AWS QC1 or equivalent certified senior welding inspector;
AWS QC1 or equivalent Certified Relevant Welding Inspector;
The manufacturer shall have a written training syllabus for certified welding inspectors. The old version did not focus on QC1
6, castings visual inspection
Not only explicitly in accordance with the MSS SP-55 inspection, and give acceptance guidelines:
Type 1 can not be accepted
Type 2 - 12, only A and B can be received