Hem Flange: Flange Width 10-25 mm, Hem Angle 180° ± 2°

Component Specifications

Definition

A hem flange is a critical structural component in automotive body panels where the edge of a metal sheet is folded over onto itself or another panel, typically at 180 degrees. This folded edge creates a reinforced seam that enhances rigidity, prevents edge deformation, improves safety by distributing impact forces, and provides a clean finish for assembly with adjacent panels through welding, adhesive bonding, or mechanical fastening.

Working Principle

The hem flange works by folding the edge of a metal panel to create a double-layered section, increasing the moment of inertia and stiffness at the edge. This prevents buckling under load, provides a secure joining surface for adjacent panels, and seals against moisture and contaminants. The folding process typically involves flanging, pre-hemming, and final hemming stages in stamping operations.

Materials

Cold-rolled steel (CRS), galvanized steel, aluminum alloys (e.g., AA5xxx, AA6xxx), advanced high-strength steel (AHSS), ultra-high-strength steel (UHSS). Thickness typically ranges from 0.6mm to 2.0mm depending on application and material strength.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Hem Angle	180° ± 2°
Bend Radius	1-3 mm
Flange Width	10-25 mm
Surface Finish	Ra 1.6-3.2 μm
Flatness Tolerance	±0.5 mm

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 2768, DIN 6930, SAE J911, VDA 238-100

Parent Products

This component is used in the following industrial products

Automotive Body Panels

Structural and aesthetic exterior components that form the outer shell of a vehicle.

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Engineering Analysis

Risks & Mitigation

Edge cracking during forming
Springback variation
Corrosion at folded interface
Dimensional inconsistency affecting assembly
Surface defects from tooling wear

FMEA Triads

Trigger: Insufficient material ductility or improper tool design
Failure: Edge cracking during hemming operation
Mitigation: Material testing for formability, optimized bend radii, controlled strain paths, and proper lubrication

Trigger: Material springback variation
Failure: Dimensional inaccuracies affecting panel fit
Mitigation: Compensation in tool design, process monitoring, material consistency controls, and post-hem calibration

Trigger: Trapped moisture in hem cavity
Failure: Corrosion leading to structural weakening
Mitigation: Hem sealant application, drainage design, corrosion-resistant coatings, and quality inspection

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

±0.3 mm for critical dimensions, ±0.5 mm for non-critical dimensions per ISO 2768-m

Test Method

Coordinate measuring machine (CMM) inspection, gap and flush measurement, cross-section analysis, corrosion salt spray testing per ASTM B117

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

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Inspection readiness

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Supplier transparency

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Manufacturers of Hem Flange

Manufacturer profiles associated with Hem Flange.

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Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review

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Frequently Asked Questions

What is the primary function of a hem flange in automotive body panels?

The primary functions are structural reinforcement to prevent edge deformation, providing a secure joining surface for adjacent panels, improving crash energy management, and creating a clean aesthetic finish.

What materials are commonly used for hem flanges?

Common materials include cold-rolled steel, galvanized steel for corrosion resistance, aluminum alloys for weight reduction, and advanced high-strength steels for enhanced safety performance.

How are hem flanges manufactured?

Hem flanges are typically created through progressive stamping dies that perform flanging, pre-hemming, and final hemming operations in sequence, often using robotic hemming cells for precision and consistency.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Hem Flange