3” Galvanized Pipe

Specifications

Item	3 Inch Galvanized Pipe
Standards	ASTM A53 Grade B, BS 1387, EN 10255
Material	Q195, Q235B, ASTM A53 Gr.B
Process	ERW Welded / Seamless Piercing + Hot‑Dip Galvanized / Pre‑Galvanized
Secondary Processing	Fixed‑length cutting, deburring, beveling, threading, grooving, anti‑corrosion treatment
Tests	Hydrostatic test, flattening test, zinc coating thickness test, visual inspection & NDT
MOQ	10 tons

Dimensional Data

Item	Value
Nominal Size	3 Inch, DN80
OD	88.9 mm (3.5 Inch)
Common Wall Thickness	SCH 40‑5.49 mm (0.216 Inch)
Inner Diameter	SCH 40‑ approx. 77.9 mm
Unit Weight	approx. 11.29 kg/m
Weight per 6‑meter Piece	approx. 67.7 kg
Available Length	1‑12 m

Product Advantages

1. Outstanding anti‑corrosion performance: Uniform and compact zinc layer metallurgically bonded to substrate. Zinc‑iron alloy layer plus outer zinc coating isolate steel substrate from external environment and greatly reduce rust risk.
2. Stable mechanical performance: Working pressure ranges from 1.6‑4.0 MPa under regular service conditions. ASTM A53 Grade B reaches minimum tensile strength ≥415 MPa. Good impact‑resistance and deformation‑resistance satisfy general civil and industrial load requirements.
3. Well‑balanced dimension: Flow capacity sits between 2‑inch and 4‑inch pipe. Ideal for building water supply & drainage branch/main pipes and fire‑protection main lines. Compatible with standard elbows, tees, flanges, valves and threaded fittings.
4. Easy fabrication & nice surface finish: Adopting mature continuous hot‑dip galvanizing technology for even zinc thickness and non‑peeling smooth surface. Support cutting, NPT/BSPT threading, grooving, beveling and pipe bending.

Mechanical Properties of Common Grades

Grade	Relevant Standard	Tensile Strength (MPa)	Yield Strength (MPa)
Q235B	GB/T 3091	375~500	≥235
ASTM A53 Gr.B	ASTM A53	≥415	≥240
Q195	GB/T 3091	315~430	≥195
S235JR	EN 10255	360~510	≥235

Applications

• Municipal Water Supply & Drainage: Municipal water supply branch lines, outdoor irrigation networks. Extra anti‑corrosion treatment is required for buried installation.
• HVAC & Low‑Pressure Gas: Chilled‑water piping for central air‑conditioning, heating pipelines, plant low‑pressure gas lines (please verify local code compliance for gas service).
• Structural Engineering: Fire‑protection sprinkler main piping, guardrail steel tubes, equipment supports, building structural bracing members.
• Agriculture & Livestock: Fence posts, barrier supports, greenhouse frames, water‑supply & heating pipelines for farm facilities.

Production Process

3‑inch (3” / DN80) belongs to medium‑large‑size specification for structural and industrial piping. ERW high‑frequency longitudinal welded pipe is the mainstream compliant solution; seamless pipe is selected for high‑pressure service.

1. Base Pipe Manufacturing
   • ERW High‑Frequency Electric Resistance Welded Pipe: Hot‑rolled steel coil uncoiling → slitting → cold forming → high‑frequency resistance welding → weld bead removing → sizing & straightening → fixed‑length cutting.
2. Hot‑Dip Galvanizing Flow
   • Degreasing → Pickling → Water Rinsing → Flux Treatment → Drying → Hot‑dip galvanizing (zinc bath temperature: 440‑465°C) → Cooling → Passivation → Final Inspection.

Two Major Galvanizing Types

1. Hot‑Dip Galvanized Pipe: Thick zinc coating with strong adhesion, highest corrosion resistance. Zinc coating weight ≥500 g/m², 5‑10 times thicker than electro‑galvanized layer. Service life: 15‑30 years.
2. Pre‑Galvanized Pipe: Relatively thin zinc coating with brighter surface. Suitable for indoor dry water‑drainage systems and temporary pipelines.

Load‑Bearing Parameters

Calculated for ASTM A53 Grade B, SCH40 wall thickness 5.49 mm, OD 88.9 mm, with safety factor = 4.

Unsupported Length	Estimated Max Load‑Bearing Capacity
5 ft (1.52 m)	approx. 12,700 kg (28,000 lbs)
10 ft (3.05 m)	approx. 7,030 kg (15,500 lbs)

Span	Estimated Max Concentrated Load
5 ft (1.52 m)	approx. 2,040 kg (4,500 lbs)
10 ft (3.05 m)	approx. 1,000 kg (2,200 lbs)

Schedule	Actual Wall Thickness(mm)	Theoretical Weight(kg/m)	Max Working Pressure (PSI / MPa)
SCH 10	3.05	~6.46	approx. 280 PSI / 1.9 MPa
SCH 40 (Standard)	5.49	~11.29	approx. 480 PSI / 3.3 MPa
SCH 80 (Extra‑Heavy)	7.62	~15.27	approx. 620 PSI / 4.3 MPa

FAQ

Q1: What is the core difference between galvanized pipe and black steel pipe?

A: Galvanized pipe features zinc coating for rust protection, widely used in water‑drainage and outdoor structural projects. Black steel pipe without zinc coating delivers superior gas tightness with less zinc‑slag risk, mainly for gas conveyance. They serve different application scenarios.

A: Most gas‑engineering codes discourage or restrict galvanized pipe for gas transmission. Zinc coating may peel off under welding or high‑temperature conditions, generating zinc slag which clogs valves and meters. Compliance with local gas‑design specifications must be confirmed before use. Black Steel Gas Pipe is preferred for regular gas piping.

A: Under SCH40 wall thickness (5.49 mm), theoretical weight is approx. 11.29 kg/m. Under GB/T 3091 system with common wall thickness of 4.0 mm, unit weight reaches approx. 8.88 kg/m.

A: MTC Mill Test Certificate complying with EN 10204 3.1 / 3.2 can be issued together with shipment. Third‑party inspection by SGS, BV, and other institutes is acceptable.

Why Choose Glory Steel?

1. Full‑range galvanized pipe supply: Complete sizes covering 1/2”‑12”, abundant stock for 3‑inch specification.
2. Multi‑standard compliance: Manufactured according to ASTM A53, GB/T 3091, EN 10255 and other international standards.
3. Strict quality control: Full‑procedure inspection for zinc coating weight, dimensional tolerance and hydrostatic test.
4. One‑stop secondary processing: Cutting, threading, beveling, grooving and bending services available.
5. Reliable lead‑time: 10‑18 days delivery for regular sizes, full‑container export supported.