Overview
EN ISO 10113:2020 - titled Metallic materials - Sheet and strip - Determination of plastic strain ratio (ISO 10113:2020, Corrected version 2020-11) - specifies a standardized method to determine the plastic strain ratio (r-value) of flat metallic products (sheet and strip). Endorsed by CEN and issued as a corrected 2020 edition, this standard is used within mechanical testing of metals to quantify plastic anisotropy important for forming performance and quality control.
Key topics and requirements
- Scope and purpose: Defines how to measure the plastic strain ratio (r), a key indicator of anisotropy in sheet metals under uniaxial tensile stress.
- Definitions and symbols: Provides clear definitions for r (r = true plastic width strain / true plastic thickness strain) and related quantities such as weighted average plastic strain ratio (r_x/y) and degree of planar anisotropy (Δr).
- Test methods: Distinguishes three methods:
- Manual method - testing without extensometers.
- Semi‑automatic method - using a length extensometer only.
- Automatic method - using both width and length extensometers for higher automation and precision.
- Test pieces and equipment: Specifies requirements for test-piece orientation relative to rolling direction and the use/calibration of extensometer systems (references ISO 9513).
- Procedure and evaluation: Details preparation, testing, evaluation of r at specified plastic (engineering) strains or strain ranges, and calculation options (including use of length-change relationships derived from volume constancy).
- Quality control and error investigation: Annex A outlines methods to investigate sources of error in r-value determination; Annex B compares international symbols.
- Reporting: Specifies required information for test reports (test method used, orientations, r-values, Δr, test conditions).
Applications and who uses it
- Primary applications: Characterising sheet and strip for metal forming operations (deep drawing, stamping, bending), design of forming processes, and material specification in automotive, aerospace and appliance industries.
- Users: Metallurgists, quality and process engineers, materials testing laboratories, research institutions, and standards bodies performing mechanical testing of metals or specifying sheet metal acceptance criteria.
- Benefits: Enables consistent, comparable r-value data for assessing planar anisotropy, predicting forming behaviour, and ensuring conformity with purchase specifications.
Related standards
- ISO 6892-1 (tensile testing of metallic materials at room temperature)
- ISO 9513 (calibration of extensometer systems)
- ISO 80000-1 (quantities and units)
- EN ISO 10113:2014 (superseded edition)
Keywords: EN ISO 10113:2020, plastic strain ratio, r-value, sheet and strip, metallic materials testing, anisotropy, extensometer, mechanical testing of metals.
