How to Procure Custom Medium and Low Pressure Flanges: A Buyer's Guide

Inspection Documents Required

When ordering custom flanges, always request the following documentation for traceability and compliance:

• Material Test Report (MTR): Certifies chemical composition and mechanical properties of the raw material.
• Dimensional Inspection Report: Verifies that flange dimensions meet drawing tolerances.
• Pressure Test Certificate: If hydrostatic testing is conducted, provide test pressure and results.
• Heat Treatment Report: For normalizing, quenching, or tempering if required by material or standard.
• Third-Party Inspection Reports: If independent verification is needed, specify in the purchase order.

RFQ Checklist for Custom Flanges

To get accurate and competitive quotations, include the following in your request for quotation (RFQ):

• Flange type (weld neck, slip-on, blind, etc.)
• Nominal pipe size (NPS) and pressure class
• Material specification (with grade and standard)
• Facing type and finish (e.g., 125-250 μin Ra)
• Drawing or sketch with all critical dimensions
• Quantity and delivery timeline
• Required certificates and inspection scope
• Relevant code or customer specification references

Quality Risks in Custom Flange Procurement

Custom manufacturing introduces risks that must be managed:

• Dimensional Errors: Verify that the manufacturer uses calibrated tools and follows approved drawings. Request a sample or first article inspection for large orders.
• Material Substitution: Ensure the material is sourced from reputable mills and traceable via MTR. Request material identification testing if doubts arise.
• Improper Heat Treatment: For high-strength or corrosion-resistant flanges, incorrect heat treatment can cause premature failure. Confirm heat treatment records.
• Inadequate Surface Finish: Leakage can occur if the gasket surface is too rough or damaged. Specify finish requirements and inspect upon receipt.

Information to Provide Before Quotation

To speed up the quotation process, provide:

• Detailed drawings or dimensions
• Operating conditions (pressure, temperature, fluid)
• Applicable codes and standards
• Required certifications
• Preferred material and facing
• Quantity and delivery date

For complex projects, involving a qualified engineer during the design phase helps avoid costly mistakes.

Get Your Custom Flange Solution

Hebei Haihao Group offers custom medium and low pressure flanges tailored to your specifications. Our team ensures compliance with international standards and provides full documentation. Contact us with your RFQ for a prompt quotation.