Source: https://guthlabs.ai/docs/instruments/hardness-scale-converter-hrc-hb-hv-hrb-mohs/implementation/

instrument implementation / implementation-contract

# Hardness Scale Converter (HRC/HB/HV/HRB/Mohs) implementation

A source-bound implementation contract for Hardness Scale Converter (HRC/HB/HV/HRB/Mohs); deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t7-014

**Effect**: Computation or source lookup only

## Input and validation requirements

The principal breaks are out-of-domain hardness values that must be rejected rather than interpolated, plus ambiguity when a bare hardness number or tensile-strength unit is supplied. A lookup engine that silently extrapolates HRC 0 or HRC 1,000,000, or assumes an unlabeled scale, can return materially misleading results.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "hardness_value": 30,
    "input_scale": "HRC",
    "material_class": "steel"
  },
  "expected_outputs": {
    "HRC": 30,
    "HB": 286,
    "HV": 302,
    "approx_tensile_strength_MPa": 1010
  },
  "reference_data": {
    "table_type": "Rockwell C to Brinell/Vickers/tensile strength, steel",
    "HRC_30": {
      "HB": 286,
      "HV": 302,
      "approx_tensile_strength_MPa": 1010
    },
    "source_convention": "ASTM E140 steel conversion table convention, widely tabulated standard value"
  },
  "working": "Input is exactly the HRC 30 row. Therefore HRC = 30, HB = 286, and HV = 302 with no interpolation. The steel-table tensile estimate is 1010 MPa."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/hardness-scale-converter-hrc-hb-hv-hrb-mohs/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/hardness-scale-converter-hrc-hb-hv-hrb-mohs/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/hardness-scale-converter-hrc-hb-hv-hrb-mohs/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche7/tranche7-results.json`