Construction

SSAW/SAWH Pipe

DETAILS AND PARAMETERS

TOLERANCES

TECHNICAL SHEET

what is ssaw steel pipe?

ssaw steel pipe is made up of hot-rolled coiled steel using a double-sided submerged arc welding method. the welding process allows the steel pipes manufacturers to produce large-diameter steel pipes suitable for different applications.

what are the advantages of ssaw pipes?

ssaw steel pipe can be produced in longer length (maximum length up to 50 meters) compared to lsaw steel pipes

due to its spiral seam ssaw pipe has an accurate diameter accuracy and strength

the sizes are adjustable & can be tailored to end-users requirement

uses of ssaw spiral welded steel pipes

transporting liquids

low-pressure applications

piling pipe

under ocean water application

water lines

pipe bridge

oil & gas

drainage projects

construction piling

irrigation

boiler manufacturing

sewage treatment

thermal industry

road & highways

retaining walls

trestle

seawalls

cofferdams

harbor structure

test: chemical component analysis, mechanical properties(ultimate tensile strength, yield strength, elongation), technical properties(flattening test, bending test, blow test, impact test), exterior size inspection, hydrostatic test, pneumatic test, ultrasonic testing (ut), x-ray test.

mill test certificate: en 10204/3. 1b

third party inspection: sgs,bv, etc.

surface: lightly oiled, hot dip galvanized, electro galvanised, black, bare, varnish coating/antirust oil, protective coatings(coal tar epoxy; fusion bond epoxy, 3-layers pe)

coating standard:

ansi/awwa c104/a21.4 american national standard for cement-mortar lining for ductile-iron pipe and fittings for water

din 30670 polyethylene coatings of steel and fittings

Dimensional Tolerances for SSAW/SAWH Pipes

(Based on API 5L (45th Ed., 2022), GB/T 9711.2-2011, EN 10219-2:2021)

Dimension Category	Symbol	Standard & Pipe Range	Tolerance	Measurement Specifications
Outside Diameter (OD)	D	API 5L (DN 50-DN 2000, t 3.2-25.4mm)	- For OD ≤ 610mm: ±0.75% of nominal OD - For OD > 610mm: ±1.0% of nominal OD	Measured at 3 evenly spaced points around the pipe circumference; average value to be used
		GB/T 9711.2 (DN 100-DN 2400, t 4.0-30mm)	- For OD ≤ 800mm: ±0.5% of nominal OD - For OD > 800mm: ±0.8% of nominal OD	Use a digital caliper (accuracy ±0.01mm) or OD tape (class 1) for large diameters
		EN 10219-2 (DN 150-DN 2000, t 3.5-22mm)	- For OD ≤ 1000mm: ±0.6% of nominal OD - For OD > 1000mm: ±0.9% of nominal OD	Measurement points 避开 weld seam (min. 50mm from weld centerline)
Wall Thickness (WT)	t	API 5L (All grades: X42-X120)	- Standard tolerance: +12.5% / -10% of nominal t - Special tolerance (by req.): +10% / -8% of nominal t	Measured at 4 points (90° apart) per cross-section; exclude weld reinforcement (grind flat if needed)
		GB/T 9711.2 (Grades B, X42-X80)	- For t ≤ 12mm: +15% / -10% of nominal t - For t > 12mm: +12% / -8% of nominal t	Use an ultrasonic thickness gauge (UTG, accuracy ±0.05mm) with couplant (glycerin or oil)
		EN 10219-2 (S235-S460)	- All t ranges: +10% / -7% of nominal t (minimum tolerance: +0.3mm / -0.2mm)	Measure at least 2 cross-sections per 3m pipe length to check uniformity
Pipe Length	L	API 5L (Single random: 6-12m; Double random: 12-24m)	- Random length: +150mm / -0mm - Fixed length (by req.): +50mm / -0mm	Measured from end face to end face with a steel tape (accuracy ±1mm/m); ensure ends are square
		GB/T 9711.2 (Single random: 6-13m)	- Random length: +200mm / -0mm - Fixed length: +30mm / -0mm (L ≤ 10m); +50mm / -0mm (L > 10m)	Length tolerance excludes end bevel (if applicable: 30°-35° angle, max. 2mm root face)
		EN 10219-2 (Single random: 6-12m)	- Random length: +100mm / -0mm - Fixed length: +25mm / -0mm (any L)	Verify with a laser distance meter (accuracy ±0.1mm) for high-precision requirements
Weld Reinforcement	h	API 5L (Internal & External)	- External: ≤ 3.2mm (max.) - Internal: ≤ 2.4mm (max.) - Transition slope: ≥ 1:4	Measured with a weld gauge (type A) at 3 points along the weld (start, middle, end)
		GB/T 9711.2	- External: ≤ 2.5mm (t ≤ 10mm); ≤ 3.0mm (t > 10mm) - Internal: ≤ 2.0mm (all t)	Ensure no abrupt changes in reinforcement (max. 0.5mm variation over 100mm weld length)
		EN 10219-2	- External: ≤ 2.0mm (t ≤ 8mm); ≤ 2.5mm (t > 8mm) - Internal: ≤ 1.5mm (all t)	Internal reinforcement may be removed (by req.) to ≤ 0.5mm above pipe ID

Shape and Geometric Tolerances for SSAW/SAWH Pipes

Tolerance Type	Standard Reference	Tolerance Requirement	Testing Method
Out-of-Roundness	API 5L	≤ 1.5% of nominal OD (max. 12mm for OD > 800mm)	Calculate as (max. OD - min. OD) at a single cross-section; test 3 cross-sections per pipe
	GB/T 9711.2	≤ 1.2% of nominal OD (max. 10mm for OD > 1000mm)	Use a 3-point OD measuring fixture to record max/min values automatically
	EN 10219-2	≤ 1.0% of nominal OD (max. 8mm for OD > 1200mm)	Scan circumference with a laser profiler (resolution 0.1mm) for digital analysis
Straightness	API 5L	≤ 0.2% of total length (e.g., 2.4mm for L=12m)	Place pipe on 2 supports (1m from each end); measure max. deflection with dial gauge
	GB/T 9711.2	≤ 0.15% of total length (e.g., 1.8mm for L=12m)	Use a straightedge (length ≥2m) along pipe axis; check gap with feeler gauge
	EN 10219-2	≤ 0.1% of total length (e.g., 1.2mm for L=12m)	Laser straightness tester (accuracy ±0.05mm/m) to map the entire pipe centerline
End Squareness	API 5L	≤ 1.5mm/m (max. 3mm for pipe ends with OD ≤ 610mm)	Place a square (class 0) against pipe end face; measure gap between square and end with feeler gauge
	GB/T 9711.2	≤ 1.0mm/m (max. 2mm for all OD ranges)	Use an end squareness gauge (digital, accuracy ±0.01mm) at 4 points (90° apart)
	EN 10219-2	≤ 0.8mm/m (max. 1.5mm for OD ≤ 1000mm)	Check with a coordinate measuring machine (CMM) to map end face flatness and squareness
Weld Misalignment (Hi-Lo)	API 5L	≤ 10% of nominal t (max. 1.6mm)	Measure difference in wall thickness across weld seam with UTG; test 5 points per weld
	GB/T 9711.2	≤ 8% of nominal t (max. 1.2mm)	Use a hi-lo gauge (magnetic base, accuracy ±0.02mm) at weld centerline
	EN 10219-2	≤ 6% of nominal t (max. 1.0mm)	Scan weld seam with an ultrasonic flaw detector (UT) to record misalignment data

Notes:

All tolerances apply to as-manufactured SSAW/SAWH pipes (no post-weld machining unless specified). For pipes with special treatments (e.g., internal/external coating), tolerance adjustments must be agreed with the manufacturer.

Weld-related tolerances (reinforcement, misalignment) are critical for pressure-containing applications (e.g., oil/gas pipelines). Non-pressure applications (e.g., structural supports) may allow relaxed weld tolerances (by contract).

For high-strength grades (e.g., API 5L X80-X120, GB/T 9711.2 X80), wall thickness tolerance may be tightened to +10% / -8% to ensure structural integrity under high pressure.

Tolerance verification must be conducted at room temperature (20℃±5℃) to avoid thermal expansion/contraction errors. For pipes stored outdoors, allow 24 hours of acclimation before testing.

Chemical Composition of SSAW/SAWH Pipes (Mass Fraction, %)

Standard & Grade	C (Carbon)	Si (Silicon)	Mn (Manganese)	P (Phosphorus)	S (Sulfur)	Cr (Chromium)	Ni (Nickel)	Mo (Molybdenum)	V (Vanadium)	Nb (Niobium)	Ti (Titanium)
API 5L (45th Ed.)
- X42	≤ 0.26	≤ 0.40	0.80-1.20	≤ 0.030	≤ 0.030	≤ 0.30	≤ 0.30	≤ 0.15	≤ 0.08	≤ 0.05	≤ 0.04
- X52	≤ 0.24	≤ 0.40	1.00-1.40	≤ 0.030	≤ 0.030	≤ 0.30	≤ 0.30	≤ 0.15	≤ 0.08	≤ 0.05	≤ 0.04
- X65	≤ 0.22	≤ 0.40	1.20-1.60	≤ 0.025	≤ 0.015	≤ 0.50	≤ 0.50	≤ 0.30	≤ 0.08	≤ 0.05	≤ 0.04
GB/T 9711.2-2011
- Grade B	≤ 0.26	≤ 0.40	0.80-1.20	≤ 0.030	≤ 0.030	≤ 0.30	≤ 0.30	-	-	-	-
- X42	≤ 0.26	≤ 0.40	0.80-1.20	≤ 0.030	≤ 0.030	≤ 0.30	≤ 0.30	≤ 0.15	≤ 0.08	≤ 0.05	≤ 0.04
- X65	≤ 0.20	≤ 0.40	1.20-1.60	≤ 0.025	≤ 0.015	≤ 0.50	≤ 0.50	≤ 0.30	≤ 0.08	≤ 0.05	≤ 0.04
EN 10219-2:2021
- S235	≤ 0.20	≤ 0.55	≤ 1.40	≤ 0.035	≤ 0.035	≤ 0.30	≤ 0.30	-	-	-	-
- S355	≤ 0.22	≤ 0.55	≤ 1.60	≤ 0.035	≤ 0.035	≤ 0.30	≤ 0.30	≤ 0.10	≤ 0.05	≤ 0.05	≤ 0.04

Mechanical Properties of SSAW/SAWH Pipes

Standard & Grade	Yield Strength (Rp0.2, MPa)	Tensile Strength (Rm, MPa)	Elongation (A, ≥ %)	Impact Energy (KV2, ≥ J)	Hardness (HV10, ≤)	Weld Joint Efficiency (%)	Typical Applications
API 5L (45th Ed.)
- X42	290-440	415-565	22	≥ 40 (-10℃)	248	≥ 90	Oil/gas gathering lines
- X52	360-510	460-630	20	≥ 40 (-15℃)	269	≥ 90	Transmission pipelines
- X65	448-595	530-705	18	≥ 40 (-20℃)	285	≥ 95	High-pressure pipelines
GB/T 9711.2-2011
- Grade B	245-415	415-565	22	≥ 27 (0℃)	200	≥ 85	Water supply pipelines
- X42	290-440	415-565	22	≥ 40 (-10℃)	248	≥ 90	Oilfield pipelines
- X65	448-595	530-705	18	≥ 40 (-20℃)	285	≥ 95	Long-distance gas pipelines
EN 10219-2:2021
- S235	235-360	360-510	25	≥ 27 (20℃)	190	≥ 85	Structural supports
- S355	355-510	470-630	22	≥ 34 (-20℃)	230	≥ 90	Industrial piping systems

Notes:

All values comply with the latest versions of the referenced standards (as of 2024). For specialized grades or custom requirements, consult official standards or manufacturers.

Impact energy values are minimum requirements for the base metal. Weld metal and heat-affected zone (HAZ) impact values may vary and should be specified separately.

Mechanical properties are measured in the transverse direction relative to the rolling direction of the plate used for pipe manufacturing.

For sour service applications (H₂S-containing environments), additional requirements for sulfur content (typically ≤0.003%) and toughness apply - refer to API 5L Annex H or NACE MR0175/ISO 15156.

Weld joint efficiency is based on 100% non-destructive testing (NDT) of welds. Lower efficiency values apply for reduced NDT coverage.