1. Valve Overview

• Material: ASTM A105N (Normalized forged carbon steel)

  • Normalization improves toughness and stress resistance vs. standard A105.

  • Suitable for -29°C to 425°C; for cryogenic use, opt for A350 LF2.

• Size: 3″ (DN 80) – balances flow capacity and compactness.

• Pressure Class: 1500 LB (per ASME B16.34)

  • 1500 PSI @ 38°C; derate at higher temps (e.g., ~1000 PSI @ 400°C).

  • 

    3 Inch Gate Valve, 800LB Forged Gate Valve Supplier in china, API 602 Gate Valve, Bolt Bonnet Gate Valve Manufacturer, China ASTM A105 Gate Valve, Class 800 LB Gate Valve

---

2. Key Design Standards

---

3. Industrial Applications

• Oil & Gas: Wellheads, pipelines, manifolds (high-pressure isolation).

• Power Plants: Steam lines, boiler feed systems.

• Petrochemical: Refinery process lines, hydrogen service.

• Hydrocarbon Processing: Fire-safe designs (API 607/6FA) for flammable fluids.

---

4. Critical Selection Factors

A. End Connections

• Butt Weld (BW):

  • Pros: Leak-proof, high integrity for permanent installations.

  • Cons: Requires skilled welding; non-removable.

• Socket Weld (SW):

  • Pros: Easier assembly than BW; good for high-pressure small-bore lines.

  • Cons: Not ideal for thermal cycling.

• Flanged (RF/RTJ):

  • Pros: Easy maintenance/installation.

  • Cons: Bulkier; potential leak paths at gaskets.

Recommendation: BW for critical high-P systems; SW for compact layouts.

B. Seating & Leakage

• Metal Seats (Stellite 6/13Cr):

  • Class B leakage (API 598) – suitable for high-temp/abrasive fluids.

• Soft Seats (PTFE):

  • Class VI (zero leakage) – limited to ≤ 250°C.

C. Operation

• Manual (Handwheel/Gear):

  • Gear operators required for Class 1500 due to high seating torque.

• Actuated (Pneumatic/Electric):

  • Used in automated or remote systems (e.g., offshore platforms).

---

5. Material & Certification Requirements

• ASTM A105N:

  • Verify normalization heat treatment on Material Test Reports (MTRs).

• NACE MR0175: Essential for sour gas (H₂S) applications.

• Fire-Safe (API 607/6FA): Mandatory for hydrocarbon service.

---

6. Pressure-Temperature (P-T) Derating

Refer to ASME B16.34 for allowable pressures at elevated temps:

Always design with a safety margin!

---

7. Top Manufacturers

Tip: Look for API Monogram for valves made in API-licensed facilities.

---

8. Inspection & Testing

• Hydrostatic Test: 1.5x rated pressure (per API 598).

• Seat Leakage Test: Class B (metal seats) or Class VI (soft seats).

• Third-Party Validation: DNV, ABS, or Lloyds for critical applications.

---

9. Cost Estimate

• 3″ A105N Class 1500 BW Gate Valve: $1,500–$3,500

• With Gear Operator: +$500–$1,500

• NACE/Fire-Safe Certified: +20–30%

---

10. Installation & Maintenance Tips

• Pre-Installation:

  • Verify weld procedure specifications (WPS) for BW valves.

  • Ensure pipe alignment to avoid stress on valve body.

• Maintenance:

  • Lubricate stems regularly in corrosive environments.

  • For metal seats, periodic lapping may be needed.

---

Conclusion

The 3-inch ASTM A105N Class 1500 gate valve is ideal for high-pressure, high-temperature industrial systems where forged steel reliability is critical. Prioritize:
✅ API 602 design (forged, compact)
✅ Butt weld ends for permanent installations
✅ Stellite-seated for durability
✅ NACE/fire-safe certs if applicable

Vendor Shortlist

1. Premium Brands (API 602 Compliant)

2. Reliable Distributors

---

Technical Datasheet Template

Valve Type: Forged Steel Gate Valve (API 602)
Size: 3″ (DN 80)
Material: ASTM A105N (Normalized Carbon Steel)
Pressure Class: 1500 LB (ASME B16.34)
Design Code: API 602
End Connections: Butt Weld (BW) / Socket Weld (SW) / Flanged (RF/RTJ)
Seat Material: Stellite 6 (Standard), PTFE (Optional)
Stem Material: ASTM A182 F6a (13Cr)
Leakage Class: API 598 Class B (Metal Seat), Class VI (Soft Seat)
Temperature Range: -29°C to 425°C (A105N)
Fire-Safe: API 607/6FA (Optional)
NACE Compliance: MR0175 (If sour service)
Operation: Handwheel / Gear Operator / Actuated (Pneumatic/Electric)
Testing: Hydrostatic (1.5x rated pressure), Seat Leakage (Per API 598)

---

Procurement Checklist

1. Request from Vendors:

   • Material Test Reports (MTRs) for ASTM A105N.

   • API 598 Test Certificates (Hydro + Seat Leakage).

   • Fire-Safe/NACE Certifications (If applicable).

   • Dimensional Drawings (ASME B16.10 face-to-face).

2. Compare Quotes On:

   • Lead time (Standard: 8–12 weeks; Rush: 4–6 weeks).

   • Incoterms (FOB, CIF, etc.).

   • Warranty (Typically 12–24 months).