JIS G 3112 is a Japanese Industrial Standard that specifies requirements for steel bars used as reinforcement in concrete, including both round (plain) bars and deformed (ribbed) bars produced by hot rolling.
It is most often used as a purchasing and QA/QC specification for reinforcing steel (rebar), driving the material certification package, inspection items, and the mechanical and dimensional checks used to confirm compliance. If you need help aligning your internal test plan to the cited edition, talk with our team.
JIS G 3112: Steel bars for concrete reinforcement
JIS G 3112 is a product specification focused on defining material and product requirements for reinforcing steel bars intended for use in concrete construction. It addresses both material properties and product conformity items such as testing, inspection, marking, and purchaser information.
The standard is commonly referenced by steel producers, fabricators, construction QA teams, and laboratories supporting incoming inspection or third-party verification of reinforcing bar shipments.
Quick Definition
JIS G 3112 defines requirements for hot-rolled round and deformed steel bars (including coil forms) used to reinforce concrete, along with associated inspection, testing, marking, and reporting expectations.
What This Standard Covers
This standard covers hot-rolled steel bars intended for concrete reinforcement, including round (plain) bars and deformed (ribbed) bars. It also includes conformity elements that typically accompany a rebar specification, such as inspection and reporting.
It explicitly excludes rerolled steel bars for concrete reinforcement that are specified in a separate JIS document (JIS G 3117).
Why This Standard Matters in Testing
JIS G 3112 is frequently used as the compliance “target” when verifying reinforcing bar shipments. The standard typically drives what gets checked and documented, including mechanical performance, dimensional conformity, and traceability marking.
For labs and QA/QC teams, the practical impact is that test setup, gripping/fixturing choices, and reporting fields often need to match the exact JIS edition and the purchaser’s specified product category and size range.
Common Materials, Product Types, or Applications Covered
JIS G 3112 is used for reinforcing steel supplied as straight lengths or in coil form for concrete reinforcement applications.
- Round (plain) steel bars for reinforcement
- Deformed (ribbed) steel bars for reinforcement
- Material supplied for rebar fabrication and placement in reinforced concrete structures
Common Test or Verification Workflow
JIS G 3112 is typically applied in a specification-to-verification workflow rather than as a standalone “single test method.” In practice, it is used to define acceptance requirements while pointing to referenced test methods for execution details.
Common workflows: Mill certificate review, incoming inspection sampling, tensile testing, bend testing (as applicable), dimensional/rib geometry checks for deformed bar, mass/weight checks, chemistry verification (when required), inspection disposition, and final reporting.
Typical documentation outputs: Test reports aligned to the purchaser’s order requirements and the cited JIS edition, with traceability back to heat/lot and product marking.
Equipment Commonly Used for This Standard
Because JIS G 3112 is a product specification, equipment needs are usually driven by the referenced mechanical test methods and the specific bar type/size being confirmed.
Common equipment: Universal testing machine (UTM) sized for rebar tensile loads, rebar-appropriate grips/wedges, extensometer or strain measurement suitable for the required elongation/yield evaluation, bend test fixtures (when bend performance is required), and basic dimensional inspection tools (calipers, gauges) plus calibrated scales for mass checks.
Chemistry verification (when required): Optical emission spectroscopy (OES) or other suitable chemical analysis instrumentation commonly used for steel grade verification.
If you are comparing load frames, grip styles, or extensometry options for your rebar size range, you can request pricing for a UTM configuration matched to your workflow.
How to Read This Designation or Revision
Designation: “JIS G 3112” identifies the standard number within the JIS “G” field (iron and steel-related standards).
Revision year: When shown as “JIS G 3112:2025,” the “2025” indicates the referenced edition year. JIS G 3112 was revised on April 21, 2025, and it replaces the prior edition (JIS G 3112:2020).
Practical caution: Edition selection can affect compliance expectations (including certification transition timing), so purchasing documents and test reports should state the exact cited edition year.
Related Standards, Methods, or Frameworks
JIS G 3112 is prepared in relation to international reinforcing steel standards and also references other JIS documents for test execution and related product categories.
- ISO 6935-1 (plain bars for reinforcement) and ISO 6935-2 (ribbed bars for reinforcement)
- JIS G 3117 (rerolled steel bars for concrete reinforcement) for products excluded from JIS G 3112
- Referenced JIS test methods used for mechanical testing (such as tensile testing) and related verification activities, depending on the requirements being applied
Get help selecting a JIS G 3112 test setup
If you need a quote for a rebar-capable tensile and bend testing setup (including grips, fixtures, and extensometry), ask for a detailed quote with your bar diameters, expected yield/UTS range, and the JIS G 3112 edition you must report to.