Project: Duplex Stainless Steel Float Production (4' Ø × 20' Length Pressure Vessels)
Mandatory Process: Solution annealing heat treatment (1050–1100°C followed by rapid water quench) is required after welding to restore the 50/50 ferrite-austenite structure and prevent sigma phase embrittlement. This requires a large furnace or outsourcing.
Contamination Control: Duplex must be processed separately from carbon steel. Dedicated cutting/welding bays or thorough cleaning systems are essential to prevent iron contamination (rust).
Welding Constraints: Maximum interpass temperature 150–250°C. Low heat input required. Automated welding highly recommended to maintain consistency.
Suited for prototyping, custom builds, or startup operations. Semi-automatic equipment with skilled technicians.
| Machine Category | Equipment Specification | Automation Level | Est. Cost (USD) |
|---|---|---|---|
| Plate Cutting | High-definition CNC plasma or 6kW fiber laser, 10' × 40' table, fume extraction | CNC automatic | $800k – $1.4M |
| Plate Rolling | 4-roll hydraulic plate roll, 1/4" × 10' capacity (duplex rating), CNC crowning | CNC with manual assist | $350k – $650k |
| Dished Heads | 600-ton hydraulic press with die sets (48" dia) OR hydraulic flanging/spinning machine | Semi-auto cycle | $400k – $900k |
| Long Seam Welding | Submerged Arc Welding (SAW) or Keyhole Plasma (PAW) longitudinal seam welder | Automated | $200k – $400k |
| Assembly & Circ. Welding | Tank turning rolls (20-ton capacity) + column & boom manipulator with TIG cold wire feed | Semi-auto (operator monitored) | $300k – $600k |
| Heat Treatment* | Atmosphere-controlled furnace, 22' L × 6' W × 6' H, with integrated quench tank | Batch automated | $600k – $1.2M |
| Corrugated Line | Decoiler (5-ton), straightener, roll former (2–3mm), flying shear, stacker | Continuous auto | $250k – $450k |
| NDT & Testing | X-ray crawler, UT flaw detector, hydrostatic test pump (3000+ PSI), automated blast booth | Manual/Assist | $200k – $400k |
| Material Handling | Overhead cranes (2×), forklifts (15k lb), vacuum lifting system for plates | Manual | $300k – $500k |
| Total Equipment Investment | $3.4M – $6.4M | ||
| Building/Construction (estimate) | $2.5M – $5M | ||
True manufacturing line with parallel processing, robotic welding, and automated material flow. Requires 5+ tanks in-process simultaneously to achieve daily output.
| Machine Category | Equipment Specification | Automation Level | Est. Cost (USD) |
|---|---|---|---|
| Material Storage | Automated plate warehouse with retrieval crane (AS/RS for steel) | Fully automated | $1.5M – $3M |
| Cutting | 12kW fiber laser with dual pallet changer, automatic nesting software, bevel head preparation | Lights-out capable | $2M – $3.5M |
| Forming | CNC 4-roll with automatic plate feeding, centering, and ejection; robotic transfer to welding | Fully automated | $800k – $1.5M |
| Dished Heads | 1200-ton servo hydraulic press with quick-change die system, integrated handling robot | Robotic forming | $2M – $4M |
| Welding Cells | 3× Robotic GTAW (TIG) cells with arc viewing cameras, adaptive fill; 1× SAW station for internals | Robotic | $1.5M – $2.5M |
| Heat Treatment | Continuous roller-hearth furnace (22' length) with high-velocity water quench tunnel | Continuous flow | $3M – $5M |
| Finishing & Test | Automated hydrotest chamber, robotic surface inspection, passivation line | Automated | $1M – $2M |
| Corrugated Line | High-speed duplex roll former (40+ m/min), automatic stacking/packaging | Fully automated | $600k – $1.2M |
Material Flow
| AGV fleet (5+ units), automated roller conveyors, buffer stations |
Fully automated |
$1.5M – $3M |
|
| Total Equipment Investment | $13M – $25M+ | ||
| Building/Construction (estimate) | $8M – $15M | ||
| Item | Details | Cost Impact |
|---|---|---|
| ASME Certification | U-Stamp accreditation for pressure vessels: quality manual, NDT procedures, third-party audits | $50k – $150k initial + annual |
| Welding Procedure Qualification | WPS/PQR development for duplex specific (restricted heat input, interpass temp), welder training | $25k – $75k |
| Raw Material Inventory | Duplex 2205 plate: ~$6–$9/lb. One set of 4 tanks requires ~15,000 lbs plate | $90k – $135k per seastead |
| Tooling & Dies | Dished head dies (2:1 elliptical), corrugation roll sets, backup rolls | $100k – $300k |
| Environmental Systems | Wastewater treatment for pickling/passivation (HF/HNO3 hazards), fume capture | $200k – $500k |
For a Seastead Startup: Begin with Scenario A equipment but outsource the heat treatment and dished head forming initially. Purchase standard tank heads from a supplier (e.g., Bradford Bright or Fort Vale) to eliminate the $400k–$900k press investment. This reduces initial capital to ~$2.5M–$4M and allows production validation before scaling.
Upgrade to Scenario B only after securing contracts for 50+ seasteads to justify the automated line and continuous furnace. The jump from 1/week to 1/day is not linear—it requires a paradigm shift from fabrication to manufacturing.