I. What is AS 1074?
AS 1074 is the Australian national standard for general-purpose welded steel pipes. It primarily specifies the material, dimensions, tolerances, mechanical properties, and testing requirements for welded steel pipes. This standard applies to non-high-pressure, general-purpose welded steel pipes.
II. Chemical Composition and Mechanical Properties of AS 1074 Welded Steel Pipes
i. Chemical Composition
| Element | Content Range (Typical Value) |
|---|---|
| C (Carbon) | ≤ 0.20% |
| Mn (Manganese) | 0.30–1.20% |
| P (Phosphorus) | ≤ 0.045% |
| S (Sulfur) | ≤ 0.045% |
| Si (Silicon) | ≤ 0.35% (some manufacturers do not strictly require this) |
ii. Mechanical properties
| Item | Typical Requirements / Common Range |
|---|---|
| Yield Strength | 200–250 MPa (typical value) |
| Tensile Strength | 320–410 MPa |
| Elongation | ≥ 20% (commonly 18–25%) |
| Impact Properties | Generally no mandatory requirement (for standard general-purpose applications) |
iii. Weld Performance Requirements
AS 1074 specifies the following requirements for welds:
The weld must be continuous, smooth, free of cracks, burn-through, and incomplete penetration.
The commonly used process is ERW (Electrical Resistance Welding).
Upon customer request, the following tests can be performed:
Flanging test
Flattening test
Hydraulic pressure test (medium to low pressure levels)
III. AS 1074 Common Specifications and Dimensions of Welded Steel Pipes
| Nominal Size (DN) | Outer Diameter OD (mm) | Wall Thickness WT (mm) | Standard Length (m) |
|---|---|---|---|
| 8 | 12.7 | 1.2 – 2.0 | 6 |
| 10 | 17.2 | 1.6 – 2.0 | 6 |
| 15 | 21.3 | 1.8 – 2.6 | 6 |
| 20 | 26.9 | 1.8 – 2.6 | 6 |
| 25 | 33.7 | 2.0 – 3.2 | 6 |
| 32 | 42.4 | 2.0 – 3.2 | 6 |
| 40 | 48.3 | 2.0 – 3.2 | 6 |
| 50 | 60.3 | 2.3 – 3.6 | 6 |
| 65 | 76.1 | 2.3 – 4.0 | 6 |
| 80 | 88.9 | 2.8 – 4.0 | 6 |
| 90 | 101.6 | 2.8 – 4.5 | 6 |
| 100 | 114.3 | 3.0 – 4.5 | 6 |
| 125 | 139.7 | 3.0 – 4.8 | 6 |
| 150 | 165.1 | 3.4 – 5.0 | 6 |
| 200 | 219.1 | 4.0 – 6.0 | 6 (customizable 12) |
| 250 | 273.1 | 4.5 – 6.4 | 6 (customizable 12) |
| 300 | 323.9 | 4.8 – 6.4 | 6 (customizable 12) |
Tolerance Requirements:
(1) Outer Diameter Tolerance
OD ≤ 48.3 mm: ±0.40 mm
48.3 mm < OD ≤ 114.3 mm: ±0.75% OD > 114.3 mm: ±1.0%
(2) Wall Thickness Tolerance
±10% (Commonly used in the industry)
(3) Length
Standard length: 6.0 m
Optional: Random length / 6.1 m / 12 m standard length
Custom cutting is allowed
Optional Surface Treatments:
Black pipe
Oil or anti-rust paint
Electro-galvanized
Hot-dip galvanized
IV. Differences between AS 1074 Black Pipe and Galvanized Pipe
i. Black Pipe vs. Galvanized Pipe – Comparison Table
| Item | Black Steel Pipe | Galvanized Pipe |
|---|---|---|
| Surface Treatment | Not galvanized, may be oiled or painted | Hot-dip galvanized or electro-galvanized |
| Corrosion Resistance | Moderate | High, suitable for outdoor or humid environments |
| Cost | Lower | Higher (due to zinc coating cost) |
| Service Life | Medium | Longer, lower maintenance cost |
| Suitable Applications | Indoor, neutral environments | Outdoor, humid areas, water supply, corrosive environments |
| Maintenance Requirement | May require repainting or rust prevention | Generally requires no additional corrosion protection |
| Common Uses | Building, structural, fire protection, internal municipal works | Fire protection, gas, water supply, outdoor projects |
V. Application Areas of AS 1074 Welded Steel Pipe
i. Construction Engineering
Applicable Products: Black pipe / Galvanized pipe
Application Notes: AS 1074 steel pipe is widely used in the construction industry due to its moderate strength, reasonable cost, and ease of processing.
Typical Uses:
Building piping networks (water supply, drainage, air conditioning piping)
Structural supports, hangers
Handrails, fences, guardrails
Scaffolding pipes, lightweight structural components
Indoor fire sprinkler system piping
Selection Recommendations:
Indoor: Black pipe is sufficient
Outdoor or high-humidity environments: Galvanized pipe is recommended
ii. Fire Protection Systems
Applicable Products: Black Pipe / Galvanized Pipe
AS 1074 pipes are commonly used in medium and low-pressure fire protection systems to meet the needs of sprinklers, fire hydrants, etc.
Typical Applications:
Fire Sprinkler Piping
Terminal Water Distribution Piping
Fire Hydrant Water Supply Branch Lines
Fire Pump Room Piping
Selection Recommendations:
Indoor Sprinkler Systems: Typically use black pipes (painted red)
Outdoor Fire Hydrant Systems: Galvanized pipes are recommended.
iii. Water Supply and Drainage Systems
Applicable Products: Galvanized Pipes / Black Pipes
AS 1074 is easy to assemble, has moderate pressure resistance, and is suitable for residential, commercial, and industrial water supply.
Typical Applications:
Indoor cold and hot water piping in buildings
Industrial park water supply networks
Agricultural irrigation piping
Industrial circulating water or cooling water systems
Selection Recommendations:
Indoor cold water: Black or galvanized pipes are both suitable.
Outdoor or long-term humid environments: Galvanized pipes are preferred.
iv. Gas Piping Systems
Applicable Products: Galvanized Pipes
Used for low-pressure gas transmission (LPG/Natural Gas).
Typical Applications:
Building indoor gas pipelines
Residential gas branch lines
Hotel and kitchen gas systems
Selection Recommendations:
Most gas regulations require the use of galvanized pipes (corrosion resistant).
Direct gas transmission using black pipes is not recommended.
v. General Industrial Applications
Applicable Products: Black tubing / Galvanized tubing
Suitable for medium and low pressure liquid and gas transportation and equipment connection piping.
Typical Applications:
Compressed air systems
Low-pressure steam transmission lines
Plant process piping
Equipment frames and supports
Steel structural components
Selection Recommendations:
Ordinary workshop environments: Black tubing
Corrosion-prone, outdoor, or dusty/humid environments: Galvanized tubing
vi. Agriculture and Infrastructure
Applicable Products: Galvanized Pipe (Corrosion Resistant)
Suitable for long-term outdoor use; corrosion resistance is paramount.
Typical Applications:
Farm water supply lines
Greenhouse frames and pergolas
Agricultural sprinkler irrigation systems
Municipal pipeline support structures
Bridge or road railings
Selection Recommendations:
Outdoor, long-term exposure: Galvanized pipe preferred
VI. AS 1074 Selection Guide for Welded Steel Pipes
| Selection Dimension | Key Points | Recommended Pipe Type | Notes / Applications |
|---|---|---|---|
| Usage Environment | Indoor, dry | Black Steel Pipe | Indoor water supply, indoor fire protection, furniture frames, etc. |
| Outdoor, humid, rainy | Galvanized Pipe | Outdoor water supply, outdoor fire protection, bridge railings, greenhouse structures | |
| Medium Type | Water, air, low-pressure steam | Black / Galvanized Pipe | Surface treatment depends on environment |
| Gas, corrosive fluids | Galvanized Pipe | Follow gas regulations or corrosion requirements | |
| Pressure Level | Medium–low | Black / Galvanized Pipe | AS 1074 mainly used for medium–low pressure |
| High (not applicable) | Not recommended | AS 1074 not suitable for high-pressure fluids | |
| Corrosion Resistance | General indoor | Black Steel Pipe | Can be painted or oiled later |
| Long-term outdoor / humid | Galvanized Pipe | Hot-dip or electro-galvanized layer for longer service life | |
| Structural Use | Brackets, frames, railings | Black Steel Pipe | Easy to process and weld, low cost |
| Exposed structures or load-bearing | Galvanized Pipe | Corrosion protection while ensuring structural stability | |
| Installation & Maintenance | Easy, regular maintenance | Black Steel Pipe | Low cost, can be repainted or oiled as needed |
| Difficult maintenance | Galvanized Pipe | Long-term durability with minimal extra protection | |
| Budget Consideration | Low budget | Black Steel Pipe | Cost-effective, suitable for large-scale projects |
| Long-term durability | Galvanized Pipe | Slightly higher cost, but low maintenance and long lifespan |