C&N Hongcheng welcome LONG PHU 1 THERMAL POWER PLANT team visit

On 16th April 2026, a technical delegation from LONG PHU 1 Thermal Power Plant conducted a comprehensive factory audit and engineering review visit at our alloy steel pipe, fitting, and forging manufacturing facility.

The visit focused on evaluating our production capability, engineering design control, material traceability system, and compliance with international standards for high-temperature power plant applications, particularly for ASTM A335 P91 seamless pipes and ASTM A234 WP91 forged fittings.

As a qualified supplier in the energy and thermal power sector, our facility demonstrated full capability in manufacturing and quality control for critical alloy piping systems used in ultra-supercritical steam conditions.

Project Scope – Alloy Steel P91 Material System

The project mainly involves supply of:

• ASTM A335 P91 seamless alloy steel pipe
• ASTM A234 WP91 forged fittings (elbows, tees, reducers, caps)
• Special bends, transition pieces, and fabricated components

Material Engineering Overview

ASTM A335 P91 – Seamless Pipe

P91 is a 9Cr-1Mo-V-Nb ferritic alloy steel designed for high-pressure, high-temperature service.

Key engineering properties:

• Designed for creep resistance up to ~600°C
• Excellent long-term rupture strength
• Micro-alloy strengthening (V + Nb carbides)
• Requires strict heat treatment: normalizing + tempering
• Fully traceable heat number system required

Typical applications:

• Main steam lines
• Reheater and superheater piping
• Boiler headers in thermal power plants

ASTM A234 WP91 – Forged Fittings

WP91 fittings are designed to match P91 pipe chemistry and mechanical properties.

Key features:

• Fully forged construction
• Heat treated to match pipe mechanical properties
• Used in welded high-pressure systems
• Strict dimensional and NDT requirements per ASME B16.9 / B16.11

Factory Audit Scope

During the audit, the buyer team inspected:

• Alloy pipe production line (seamless hot finishing)
• Forged fitting manufacturing workshop
• Hot induction bending and expansion facilities
• Heat treatment furnaces (normalizing & tempering)
• NDT laboratory (UT, RT, hardness, PMI testing)
• Material traceability system (MTC control and heat mapping)
• Final inspection and hydrostatic testing station

Technical discussions were conducted between engineering teams covering:

• Manufacturing route selection
• Expansion ratio control
• Thickness tolerance management
• Raw material sourcing strategy
• Design thickness calculation methodology

BUYER TECHNICAL QUERIES (Engineering Review Record)

The following technical clarifications were formally raised by the buyer for engineering submission and approval:

1. Manufacturing Route Definition (MTO Level)

For each fitting size in the MTO, please specify:

• Hot bending
• Cold forming / cold finished
• Expansion process
• Stock / standard supply

2. Expansion-Manufactured Fittings – Technical Details Required

For fittings produced by expansion method, provide:

1. Original size vs final size
   • Expansion ratio and number of expansion steps
2. Expansion production capacity
   • Number of expansion lines available
   • Typical lead time per line
3. Thickness control methodology
   • How wall thickness (WT) is controlled during expansion process
4. Heat treatment load management
   • Furnace capacity and workload balancing for expanded components

3. Non-Standard Fitting Manufacturing Process

Provide detailed process information for:

(1) Medium size heavy wall

• DN250 and DN200
• Thickness: 38mm

(2) Large size thin wall

• DN750 and DN700
• STD thickness: 9.53mm

Required:

• Process route (forging / machining / fabrication)
• Thickness tolerance control method
• Dimensional stability assurance

4. Raw Material Mill Profile

Submit full details of:

• Approved steel mills list
• Certification scope (ASTM/ASME compliance)
• Heat treatment capability of mills
• Historical qualification records

5. Special Thickness Calculation Methodology

Provide detailed engineering calculation sheets for items such as:

• DN550 × 76mm
• DN500 × 69mm
• ID356 × 66mm

Including:

• Applicable design codes (ASME B31.3, ASTM A234, ASTM A105, etc.)
• Design input parameters:
  • Design pressure
  • Design temperature
  • Corrosion allowance
  • Mill tolerance
• Step-by-step wall thickness derivation
• Final required thickness + tolerance justification

6. Minimum Order Quantity (MOQ)

Clarify:

• Any MOQ limitations for special sizes or non-standard fittings
• Impact on production planning and pricing

7. In-House vs Outsourced Manufacturing Scope

Define clearly:

• Items manufactured internally
• Items outsourced to external suppliers

For outsourced items:

• Provide full MTC and inspection/test reports
• Ensure full traceability compliance

8. Mother Pipe (Raw Material) Availability & Procurement

Clarify:

• Stock availability of mother pipes for fitting production
• Lead time for non-stock procurement
• Required pipe specifications

Buyer also proposed coordination of pipe sourcing:

• Customer may share supplier contacts for consolidated procurement planning

9. Free Issue Pipe Calculation Sheets

Provide detailed engineering calculation for:

• Bends
• Special elbows
• Transition pieces

Including:

• Pipe length
• Pipe size
• Thickness (THK)
• Dimensional requirements
• Fabrication allowance

10. Engineering Drawings for Approval

Submit for review:

• All bend designs
• Special-size olets (above DN250)
• Transition piece drawings

Audit Outcome

The audit concluded with positive technical discussions and strong alignment on engineering requirements. The buyer acknowledged the facility’s capability in producing high-integrity P91 alloy piping systems, particularly in:

• Controlled expansion processes
• Heat treatment precision
• Material traceability system
• Compliance with ASME/ASTM standards

Further technical documentation submission and engineering approval review will be carried out in the next phase.

Conclusion

The successful factory audit by LONG PHU 1 Thermal Power Plant marks an important milestone in cooperation for the supply of ASTM A335 P91 / ASTM A234 WP91 high-pressure alloy piping systems.

This engagement further strengthens mutual confidence in executing critical thermal power infrastructure projects requiring high-performance alloy steel materials under severe operating conditions.