{
  "title": "Austenitic stress-relief choice and contrary mechanisms",
  "scope": "One adopted 300-series stainless selection and treatment method; not a universal SCC or hydrogen qualification rule. Material/service decision precedes cycle execution.",
  "inputs": [
    "Actual grade/carbon specification and stabilization condition",
    "Prior welding/treatment and proposed accumulated thermal history",
    "Internal aqueous chlorides/caustic/known SCC, water injection and local low points",
    "External saltwater/washdown/insulation/coast and operating temperature",
    "Leak consequences and replacement access/lead time/cost",
    "Absolute hydrogen partial pressure and preceding method exclusions"
  ],
  "comparison": [
    {
      "situation": "Defined internal SCC with material suitable for the route",
      "direction": "Consider stress reduction",
      "contrary_input": "Intergranular attack or sensitization can oppose added thermal exposure"
    },
    {
      "situation": "Intergranular attack is the greater concern or susceptible non-L material",
      "direction": "Method favors no stress relief; low-carbon material under applicable acid-service route",
      "contrary_input": "No-SCC-immunity or general acid-material approval follows"
    },
    {
      "situation": "External chloride with consequential leak or difficult replacement",
      "direction": "Consider actual exposure and consequence route",
      "contrary_input": "Internal stream alone does not characterize outside environment"
    },
    {
      "situation": "Locally defined high-pressure hydrogen",
      "direction": "Leak consequence contributes to selection",
      "contrary_input": "Material/IGC exclusions and absolute partial-pressure reference remain; not complete hydrogen envelope"
    }
  ],
  "bounded_conditions": {
    "carbon_specification_mass_percent": {
      "non_L_304_316_317_max": 0.08,
      "L_grade_max": 0.03
    },
    "internal_service": {
      "known_SCC_temperature_above_F": 140,
      "aqueous_chloride_above_ppm": 50,
      "caustic_general_temperature_above_F": 140,
      "caustic_high_concentration_above_wt_percent": 30,
      "high_concentration_caustic_temperature_above_F": 110
    },
    "selection_temperature_disagreement": {
      "large_pipe_general_exclusion_below_F": 150,
      "detailed_internal_service_boundary_F": 140,
      "disposition": "Preserve each local scope; no lower-bound shortcut or averaged cutoff"
    },
    "external_service": {
      "temperature_above_F": 200,
      "saltwater_route": "Detailed prose separately includes saltwater firewater or washdown",
      "coastal_route": "Coast plus personnel/plant-reliability leak consequence OR long replacement lead time/high cost",
      "limit": "Condensed route does not reproduce the standalone saltwater branch; no elimination guarantee"
    },
    "hydrogen": {
      "partial_pressure_above_psia": 100,
      "limit": "Absolute reference in detailed method; condensed psi label and preceding branch questions retained as qualification, not universal priority"
    },
    "selected_joint_coverage": {
      "NPS_2_and_above": "Selected butt welds",
      "below_NPS_2": "All welds through first block valve under the selected method",
      "small_pipe_selection": "Separate small-pipe selection retains known chloride-cracking scope"
    }
  },
  "fabrication_cycle": {
    "hold_temperature_F": [
      1550,
      1650
    ],
    "hold_h_per_in_nominal_wall": 1,
    "minimum_hold_h": 1,
    "cooling": "Still air with heat source removed",
    "limit": "Only after material/service route selected; not stabilization or casting solution-treatment substitution"
  },
  "hypothetical_hold_examples": [
    {
      "nominal_wall_in": 0.5,
      "proportional_hold_h": 0.5,
      "minimum_hold_h": 1,
      "required_hold_h": 1
    },
    {
      "nominal_wall_in": 1.5,
      "proportional_hold_h": 1.5,
      "minimum_hold_h": 1,
      "required_hold_h": 1.5
    }
  ],
  "verification": "Actual heated coverage, metal temperature record, cooling and property/examination requirements remain; hypothetical arithmetic supplies no acceptance."
}