ASTM A192/A192M – Standard Specification for Seamless Carbon Steel Boiler Tubes for High Pressure Service

Scope  

This specification covers minimum wall thickness, seamless carbon steel boiler and super heater tubes designed for high-pressure service in stationary boilers, super heaters, and heat exchangers. These tubes are suitable for high temperature and high pressure environments where reliability is critical.  

Ordering Information  

Purchasers must specify the following when ordering:  

l  Quantity (total length or number of tubes)  

l  Material (seamless carbon steel boiler tube)  

l  Dimensions (nominal outside diameter and minimum wall thickness, in inches [A192] or millimeters [A192M])  

l  Length (cut lengths with tolerances or random lengths)  

l  ASTM Designation (A192 for inch-pound units, A192M for metric)  

l  Testing Requirements (hydro-static test, nondestructive electric test, or expanded flattening test)  

l  Certification (if mill test reports are required)  

l  Additional Requirements (special marking, heat treatment, or supplementary testing)  

 Material & Manufacture  

 Steel making Process: Open hearth, electric furnace, or basic oxygen process.  

 Manufacturing Method: Tubes are hot-finished or cold-drawn, then stress relieved or annealed to ensure ductility and strength.  

 Heat Treatment: Mandatory to meet mechanical property requirements.  

Chemical Composition (%)  

| Element | Requirement |  

| Carbon (C) | 0.06–0.18 |  

| Manganese (Mn) | 0.27–0.63 |  

| Phosphorus (P) | ≤ 0.035 |  

| Sulfur (S) | ≤ 0.035 |  

| Silicon (Si) | ≥ 0.10 (for deoxidation) |  

Mechanical Properties  

| Property | Requirement |  

| Tensile Strength | ≥ 325 MPa (47,000 psi) |  

| Yield Strength | ≥ 180 MPa (26,000 psi) |  

| Elongation (in 2 in./50 mm) | ≥ 35% |  

| Hardness (optional) | ≤ 72 HRB (Rockwell B) |  

Test Requirements  

 Mandatory Tests  

 Hydro-static Test: Each tube must withstand a specified water pressure (≥ 70 bar / 1,000 psi for 5 sec) without leakage.  

 Nondestructive Electric Test (NDE): If hydro-static testing is waived, eddy current or ultrasonic testing must be performed.  

 Optional/Special Tests  

 Flattening Test: A sample must flatten to a specified distance without cracking.  

 Flaring Test: A cone expansion test to verify ductility (if required).  

 Hardness Test: Optional, per agreement.  

 Dimensions & Tolerances  

l  Outside Diameter: Permissible variations (±0.8% for cold-drawn, ±1.0% for hot-finished).  

l  Wall Thickness: Must meet minimum requirements with tolerances (±10% for most sizes).  

l  Length:  

l  Cut lengths: ±3.2 mm (1/8 in.) for lengths ≤ 7.3 m (24 ft).  

l  Random lengths: 4.9–12.2 m (16–40 ft).  

 Inspection & Certification  

 Inspection: Manufacturer performs tests; purchaser may witness or request third-party inspection.  

 Certification: Mill test reports (chemical analysis, mechanical properties, and test results) provided upon request.  

Marking Requirements  

Each tube must be marked with:  

 ASTM standard (A192/A192M)  

 Manufacturer’s name or trademark  

 Nominal size (OD and wall thickness)  

 Heat number or traceability code  

 Keywords  

 Seamless carbon steel tubes  

 High-pressure boiler tubes  

 Super-heater tubes  

 Heat exchangers  

 ASME Code compliance  

 Key Differences from ASTM A179/A179M  

 A192/A192M is specifically for high-pressure boilers, while A179/A179M is for heat exchangers/condensers.  

 A192 has stricter wall thickness controls due to high-pressure demands.  

 A192 requires mandatory heat treatment, while A179 may be supplied as-drawn.  

This standard ensures safety and performance in critical high temperature, high pressure applications.  

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