I. Standard System
Applicable Standards
Type A (Thick Shank): JB/T 1704-2015 "Double-End Studs for Valves"
Shank diameter = Nominal thread diameter (e.g., M16 corresponds to φ16⁻⁰.¹⁸mm, h12 tolerance)
Type B (Thin Shank): HG/T 20613-2014 "Fasteners for Steel Pipe Flanges"
Shank diameter ≈ Thread minor diameter (e.g., M16 minor diameter: 14.2±0.2mm)
Thread Accuracy
Type A: 6g grade (GB/T 197-2018)
Type B: 7H/8g grade (ASME B1.13M)
II. Material Specifications
General Materials
| Category | Typical Grade | Standard Reference |
|---|---|---|
| Stainless Steel | 06Cr19Ni10 (304) | GB/T 20878-2007 |
| Alloy Structural Steel | 42CrMoA | GB/T 3077-2015 |
Pressure Vessel-Specific Materials
ASTM A193-B7: Requires EN 10204 3.2 material certificate and high-temperature creep test reports.
Domestic Equivalent: 14Cr1MoR (GB 713-2014), subject to design modification approval.
III. Manufacturing Processes
Type A Production Process
Cold Heading → Stress Relief Annealing (400-450℃/2h) → Thread Rolling
Cold heading compression ratio ≤2.5:1 (for 304 stainless steel).
Type B Production Process
Wire Peeling (Ra≤1.6μm) → Cold Drawing (Deformation ≤15%) → Thread Forming
Reduction die taper angle: 12°±0.5°.
IV. Installation & Maintenance
Anti-Loosening Configuration
DIN 980-VM lock nuts + Nord-Lock washers.
Preload control per VDI 2230 standard.
Maintenance Criteria
| Inspection Item | Replacement Threshold | Detection Method |
|---|---|---|
| Thread Engagement Height Loss | >30% | Thread profile measurement |
| Axial Clearance | >0.08mm | Laser displacement sensor |
V. Compliance Requirements
Regulatory Basis
TSG 21-2016 Article 3.2.1: Pressure vessel materials must match design documentation.
GB 150.4-2019 Clause 6.3: 100% magnetic particle inspection for load-bearing bolts.
Testing & Certification
Intergranular corrosion test: Method E per GB/T 4334-2020.
Mechanical performance test: High-temperature tensile test (≥450℃).
