This standard specifies the types and characteristics of surface defects of valves, flanges, fittings and their pressure retaining castings.
This standard is applicable to the visual inspection and acceptance of the surface quality of valves, flanges, fittings and their pressure retaining castings.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 12229 General purpose industrial valves — Specification of carbon steel castings
GB/T 12230 General purpose industrial valves — Specification of stainless steel castings
JB/T 5263 Specification for steel casting for power station valves
JB/T 6439 Methods of magnetic examination for valves
JB/T 6440 Methods of radiographic examination for steel castings valves
JB/T 6902 Methods for liquid penetrant examination of valves
3 Surface quality evaluation
3.1 Cast steel shall be inspected after cleaning, dressing and painting, compared with the surface of cast steel according to the photos specified in this standard (see Clause 5), and evaluated for various defects.
3.2 This standard collects 12 types of surface defects (see 5.1 to 5.12, and each defect type includes 5 example photos represented by A, B, C, D and E. In each defect, 2 example photos of A and B indicate that defects of this degree are acceptable (qualified), and 3 example photos of C, D and E are unacceptable (unqualified) defects. The guiding principles of this standard shall be considered acceptable for defects that are significantly smaller than unacceptable defects.
3.3 This standard photo comes from the actual casting. The photo shows the surface defects of casting. Each type of surface defects can only be judged by comparing the series of photos of the same type.
3.4 In view of the possible problems if the same standard is used to judge castings with large differences in specifications and wall thicknesses, the photos provided in this standard are examples of drawings specifying the actual dimensions of any 100 mm × 125 mm area on the surface of castings.
4 Description of rating photos
4.1 This standard provides 60 rating photos showing various casting defects that can be seen by visual observation. The description of all defect types [type a) ~ type 1)] in the rating photo is only applicable to surface defects, not internal defects.
4.2 The types and characteristics of various surface defects are described as follows:
——Type a) Crack: Linear cracking on the surface of cast steel due to internal and external stresses. Generally, obvious surface cracks are unqualified.
Foreword i Introduction iii 1 Scope 2 Normative references 3 Surface quality evaluation 4 Description of rating photos 5 Rating photos Annex A (Informative) Structural changes and description of this standard with respect to ANSI/MSS SP-55-2011 Table A.1 Comparison between this standard and ANSI/MSS SP-55-2011 in clause and subclause numbers
Valve cast steel visual quality requirements
1 Scope
This standard specifies the types and characteristics of surface defects of valves, flanges, fittings and their pressure retaining castings.
This standard is applicable to the visual inspection and acceptance of the surface quality of valves, flanges, fittings and their pressure retaining castings.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 12229 General purpose industrial valves — Specification of carbon steel castings
GB/T 12230 General purpose industrial valves — Specification of stainless steel castings
JB/T 5263 Specification for steel casting for power station valves
JB/T 6439 Methods of magnetic examination for valves
JB/T 6440 Methods of radiographic examination for steel castings valves
JB/T 6902 Methods for liquid penetrant examination of valves
3 Surface quality evaluation
3.1 Cast steel shall be inspected after cleaning, dressing and painting, compared with the surface of cast steel according to the photos specified in this standard (see Clause 5), and evaluated for various defects.
3.2 This standard collects 12 types of surface defects (see 5.1 to 5.12, and each defect type includes 5 example photos represented by A, B, C, D and E. In each defect, 2 example photos of A and B indicate that defects of this degree are acceptable (qualified), and 3 example photos of C, D and E are unacceptable (unqualified) defects. The guiding principles of this standard shall be considered acceptable for defects that are significantly smaller than unacceptable defects.
3.3 This standard photo comes from the actual casting. The photo shows the surface defects of casting. Each type of surface defects can only be judged by comparing the series of photos of the same type.
3.4 In view of the possible problems if the same standard is used to judge castings with large differences in specifications and wall thicknesses, the photos provided in this standard are examples of drawings specifying the actual dimensions of any 100 mm × 125 mm area on the surface of castings.
4 Description of rating photos
4.1 This standard provides 60 rating photos showing various casting defects that can be seen by visual observation. The description of all defect types [type a) ~ type 1)] in the rating photo is only applicable to surface defects, not internal defects.
4.2 The types and characteristics of various surface defects are described as follows:
——Type a) Crack: Linear cracking on the surface of cast steel due to internal and external stresses. Generally, obvious surface cracks are unqualified.
Contents of JB/T 7927-2014
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Surface quality evaluation
4 Description of rating photos
5 Rating photos
Annex A (Informative) Structural changes and description of this standard with respect to ANSI/MSS SP-55-2011
Table A.1 Comparison between this standard and ANSI/MSS SP-55-2011 in clause and subclause numbers
