{
  "title": "Torque Ledger: Preload Integrity Protocol",
  "author": "Alex Carter",
  "version": "1.0",
  "date": "2026-07-18",
  "unit_system": {
    "primary": "SI",
    "imperial_fallback": true
  },
  "material_matrix": [
    {
      "standard": "ISO 898-1",
      "grade": "8.8",
      "min_tensile_MPa": 800,
      "proof_load_MPa": 640,
      "use_case": "General structural"
    },
    {
      "standard": "ISO 898-1",
      "grade": "10.9",
      "min_tensile_MPa": 1040,
      "proof_load_MPa": 900,
      "use_case": "High-load frame"
    },
    {
      "standard": "SAE J429",
      "grade": "Grade 5",
      "min_tensile_MPa": 827,
      "proof_load_MPa": 655,
      "use_case": "Mixed alloy steel"
    },
    {
      "standard": "SAE J429",
      "grade": "Grade 8",
      "min_tensile_MPa": 1034,
      "proof_load_MPa": 827,
      "use_case": "Aerospace interface"
    },
    {
      "standard": "ASTM A36",
      "grade": "-",
      "min_tensile_MPa": 475,
      "proof_load_MPa": 250,
      "use_case": "Base plate weld"
    }
  ],
  "torque_table_metric": [
    {
      "diameter": "M6",
      "pitch_mm": 1.0,
      "grade_88_Nm": 10.2,
      "grade_109_Nm": 14.8,
      "joint_type": "Panel mount"
    },
    {
      "diameter": "M8",
      "pitch_mm": 1.25,
      "grade_88_Nm": 28.5,
      "grade_109_Nm": 41.2,
      "joint_type": "Rib attachment"
    },
    {
      "diameter": "M10",
      "pitch_mm": 1.5,
      "grade_88_Nm": 62.4,
      "grade_109_Nm": 90.1,
      "joint_type": "Frame node"
    },
    {
      "diameter": "M12",
      "pitch_mm": 1.75,
      "grade_88_Nm": 118.0,
      "grade_109_Nm": 170.5,
      "joint_type": "Hull ring"
    },
    {
      "diameter": "M16",
      "pitch_mm": 2.0,
      "grade_88_Nm": 295.0,
      "grade_109_Nm": 426.0,
      "joint_type": "Dome keystone"
    }
  ],
  "protocol": {
    "sequence": "three_pass",
    "pass_targets_percent": [30, 70, 100],
    "hold_time_seconds": 3,
    "friction_coefficient_default": 0.15,
    "preload_target_percent_proof": 75,
    "star_pattern_required_for_flanges_bolts": 4
  },
  "sources": [
    {
      "name": "ISO 80000-4:2006",
      "type": "standard",
      "url": "https://4ort.xyz/entity/torque"
    },
    {
      "name": "Wikidata Q48103",
      "type": "knowledge_graph",
      "url": "https://www.wikidata.org/wiki/Q48103"
    }
  ]
}