ISO 9444-1:2009

Overview - ISO 9444-1:2009 (Continuously hot-rolled stainless steel, narrow strip and cut lengths)

ISO 9444-1:2009 specifies dimensional and form tolerances for continuously hot‑rolled stainless steel narrow strip (actual widths < 600 mm) and cut lengths taken from such strip. The standard defines what purchasers must specify, typical delivery conditions (as‑rolled U unless agreed), and the measurement methods used to verify compliance. It replaces earlier consolidated editions by splitting ISO 9444 into two parts (Part 1: narrow strip and cut lengths; Part 2: wide strip and sheet/plate).

Key topics and technical requirements

• Scope and purchaser information: Purchasers should specify delivery type, part number (ISO 9444-1), thickness (with normal or fine tolerances), width, edge and end condition (M = mill edges, T = trimmed edges; R = mill ends, C = cropped ends), length for cut lengths, and any special delivery conditions.
• Thickness tolerances: Normal and fine tolerances are given by thickness ranges and categories (A/B and FA/FB). Fine tolerances for narrow strip are valid only for deliveries of more than two coils (for cut lengths fine tolerances apply regardless of quantity).
• Width tolerances: Mill (as‑rolled) edges: 0/+15 mm unless agreed otherwise. Trimmed (slit) edge tolerances are tabulated by width and thickness.
• Length tolerances: Cut lengths have specified tolerances (e.g., +10/0 mm for lengths < 2 000 mm; proportional tolerance for longer lengths).
• Edge camber, squareness and flatness:
  • Edge camber tolerances for standard 2 500 mm cut lengths (e.g., 20 mm for w < 40 mm; 10 mm for 40 ≤ w < 600 mm), with formula for non‑standard lengths.
  • Out‑of‑squareness limited to 1% of specified width.
  • Flatness tolerance for cut lengths: 15 mm over any 2 000 mm or less.
• Coil form and delivery condition: Coils must be tightly wound and as round as possible; allowable lateral coil edge displacement: 35 mm (trimmed edges) or 70 mm (mill edges).
• Measurement methods: Defined methods and locations for measuring thickness, width, length, edge camber, squareness and flatness.

Applications and users

This standard is used by:

• Steel producers and coil slitting operations to specify and certify product tolerances.
• Purchasing departments and procurement specifying stainless steel narrow strip or cut lengths.
• Quality inspectors and metallurgical labs verifying compliance.
• Fabricators, stampers and manufacturers who require predictable dimensions for cold rolling, forming or downstream processing.

Practical benefits include clearer order specifications, consistent quality assurance, and reduced disputes over dimensional compliance.

Related standards

• ISO 9444-2 - Continuously hot-rolled stainless steel: Part 2 (wide strip and sheet/plate).
• ISO 6929:1987 - Steel products - Definitions and classification (normative reference used in ISO 9444-1).