EN 10217-7 Stainless Steel Welded Pipe
EN 10217-7 stainless steel welded pipe exterior view
EN 10217-7 welded stainless pipe production detail
EN 10217-7 stainless steel pipe surface finish close-up

EN 10217-7 Stainless Steel Welded Pipe

Product Specifications

Product Name: stainless steel welded pipe、316L Stainless Steel Welded Pipe

OD: 12.7 mm–660 mm

WT: 1.6 mm – 25 mm

Length: 6m、12m

Material: TP304, TP316, TP316L

Standard: EN 10217-7

Application: For industrial fluid conveyance, petrochemical pipelines, pharmaceutical and food/beverage process piping, high-temperature steam pipelines and hot water conveyance, pressure vessels, boilers, and general industrial piping projects.

I. Introduction to EN 10217-7 Stainless Steel Welded Pipes

EN 10217-7 stainless steel welded pipes are pressure-rated stainless steel welded pipes manufactured according to the European standard EN 10217-7. They serve as critical piping materials for industrial fluid conveyance and pressure pipelines.

This standard primarily addresses austenitic stainless steel and austenitic-ferritic stainless steel pipes, ensuring superior mechanical properties and corrosion resistance under high-temperature, high-pressure, and corrosive conditions.

II. Key Differences from Other Common Stainless Steel Welded Pipe Standards

Comparison Standard Material Type Scope of Application Pressure Level Welding Method Features
EN 10217-7 Austenitic / Austenitic-Ferritic (304/316/316L) Pressure piping, industrial fluids, chemical, food, pharmaceutical High & medium pressure TIG / MIG / ERW Strict limits on chemical composition, mechanical properties, pressure testing and weld inspection; emphasizes corrosion and pressure resistance.
ASTM A312 Austenitic stainless (304/304L/316/316L) Pressure vessels, industrial fluid transport, steam Medium & high pressure TIG / ERW Emphasizes corrosion resistance and high-temperature performance; slightly wider wall-thickness and dimensional tolerance ranges.
ASTM A269 Austenitic stainless (304/316/316L) Industrial fluid transport, low-pressure piping, food, dairy Low to medium pressure TIG / ERW Oriented to low-pressure and hygienic applications; welding and surface finish options are more flexible.
EN 10216-5 Austenitic & austenitic-ferritic stainless High-temperature boiler tubes, pressure vessels High temperature & high pressure Welded / Seamless Emphasizes high-temperature strength and heat-treatment properties; mainly for boilers and elevated-temperature service.
DIN 11850 Austenitic stainless Food, dairy, beverage Low pressure TIG / ERW Sanitary tubing standard; focuses on surface smoothness and ease of cleaning.

III. Classification of Stainless Steel Welded Pipes per EN 10217-7

(1) Classification by Material Grade

304 / 304L: Low-carbon austenitic stainless steel with good corrosion resistance, suitable for general industrial liquids and medium-to-low pressure pipelines.

316 / 316L: Molybdenum-containing austenitic stainless steel with strong chloride corrosion resistance, suitable for seawater, chemical liquids, food, dairy, and pharmaceutical process piping.

Duplex (Austenitic + Ferritic): High-strength corrosion-resistant tubing suitable for high-pressure and corrosive environments, particularly in chemical and seawater applications.

(2) Classification by Welding Method

TIG (Tungsten Inert Gas Welding): Produces uniform welds, suitable for small-diameter thin-walled pipes and sanitary pipelines.
MIG/MAG Welding: Suitable for medium-to-large diameter pipes, offering high efficiency and reliable weld quality.
ERW (Electric Resistance Welded): Suitable for medium-to-small diameter high-pressure industrial pipes, delivering uniform welds and high production efficiency.

(3) Classification by Application or Pressure Rating

Pressure Piping: Designed for high-pressure environments; welds require non-destructive testing (X-Ray / UT).
Industrial Fluid Piping: Used in medium-to-low pressure conditions, suitable for cooling water, process liquids, etc.
Sanitary Piping: Features a smooth surface and polishable finish, suitable for food, beverage, dairy, and pharmaceutical process piping.

(4) Classification by Surface Treatment

Pickling / Descaling: Provides basic corrosion resistance, suitable for general industrial liquids.
Polishing / Mirror Finishing: Meets high sanitary standards with surface roughness Ra ≤ 0.8 μm.
Coloring or Protective Coating: Used in specialized environments such as acidic/alkaline solutions, seawater, or high-temperature steam applications.

IV. EN 10217-7 Chemical Composition and Mechanical Properties of Welded Stainless Steel Pipes

(1) Chemical Composition

Grade C (%) Cr (%) Ni (%) Mo (%) Mn (%) P (%) S (%) Remarks
304 ≤0.08 18–20 8–10 — ≤2 ≤0.045 ≤0.03 General industrial fluid piping
304L ≤0.03 18–20 8–10 — ≤2 ≤0.045 ≤0.03 Low-carbon, improved weldability
316 ≤0.08 16–18 10–14 2–3 ≤2 ≤0.045 ≤0.03 Mo-bearing, enhanced chloride corrosion resistance
316L ≤0.03 16–18 10–14 2–3 ≤2 ≤0.045 ≤0.03 Low-carbon, excellent weldability and higher corrosion resistance
Duplex ≤0.03 22–25 4–6 3–4 ≤2 ≤0.03 ≤0.02 High strength & corrosion resistance, suitable for high-pressure corrosive environments

(2) Mechanical Properties

Grade Tensile Strength (MPa) Yield Strength (MPa) Elongation (%) Hardness (HRB) Remarks
304 / 304L 520–720 ≥205 ≥40 79–90 General industrial fluids and low-pressure piping
316 / 316L 520–680 ≥205 ≥40 79–90 Mo-bearing, improved corrosion and pitting resistance
Duplex 620–850 450–550 ≥25 85–95 High strength & corrosion resistance, suitable for high-pressure and corrosive service

V. EN 10217-7 Manufacturing Process for Stainless Steel Welded Pipes

(1) Forming Process
EN 10217-7 stainless steel welded tubes are formed using high-precision roll forming.
Small-diameter thin-walled tubes predominantly employ cold rolling, achieving high roundness and straightness suitable for sanitary pipelines.
Medium-to-large diameter pipes predominantly employ hot rolling to enhance ductility and toughness, meeting high-pressure service requirements.

(2) Welding Process
Welding utilizes TIG, MIG/MAG, or ERW techniques.
Welds exhibit uniformity and reliable strength, capable of withstanding various pressure ratings.
Small-diameter pipes feature smooth welds suitable for sanitary applications and low-pressure fluid conveyance.
Medium-to-large diameter pipes achieve high welding efficiency, suitable for industrial and high-pressure services.

(3) Heat Treatment Process
Solution annealing is performed after welding.
This eliminates welding stresses and stabilizes the austenitic microstructure.
It enhances the pipe’s corrosion resistance and high-temperature performance.

(4) Surface Treatment
Pipe surfaces undergo acid pickling and passivation to improve corrosion resistance.
Sanitary pipes can be polished or mirror-finished to ensure cleanliness and ease of maintenance.
Surface treatments meet requirements for food, dairy, beverage, and pharmaceutical industries.

(5) Quality Control
Strictly monitors weld quality and mechanical properties throughout manufacturing.
Ensures pipes meet specific pressure, temperature, and media conditions during selection.
The entire process guarantees dimensional accuracy and corrosion resistance per EN 10217-7 standards.

Dimensions 68624342 cm
Tensile Strength

500–700 MPa
Yield Strength

≥205 MPa
Elongation

≥35–40%
Hardness

HRB 80–95
Maximum Service Temperature

870°C (short-term)
Minimum Service Temperature

-196°C
Welding Processes

TIG, MIG, ERW
Bending Performance

Withstands 180° bending without cracking
Surface Roughness

Ra 0.8–1.6μm, polishable or mirror finish
Corrosion Resistance

High, particularly suitable for chloride and acidic/alkaline environments

FAQ

Q1: Can the pipes be used long-term in high-temperature environments?
A1: EN 10217-7 stainless steel welded pipes typically withstand temperatures around 300°C, with short-term exposure to higher temperatures possible. For prolonged high-temperature use, select appropriate pipe grades based on material type (304, 316, Duplex) and conduct regular inspections of welds and pipe bodies for oxidation or intergranular corrosion.

Q2: What types of media are these pipes suitable for conveying?
A2: 304/304L pipes are suitable for general industrial liquids and low-corrosive media; 316/316L pipes are suitable for seawater, chemical liquids, and chloride-containing media; Duplex pipes can be used in highly corrosive environments and for high-pressure liquids. Specify the media type during procurement to ensure proper material selection.

Q3: How can pitting or crevice corrosion be prevented during pipeline operation?
A3: Avoid prolonged stagnation or localized retention of corrosive liquids in pipelines. Maintain cleanliness of pickled and passivated pipe surfaces; flush periodically or add corrosion inhibitors as needed. Sanitary pipelines may undergo polishing to reduce corrosion risk.

Q4: What are the installation precautions for piping?
A4: During installation, prevent twisting, excessive bending, or stress concentration. Ensure proper alignment of pipe ends during welding or connection. Support spacing must meet requirements for pipe diameter and wall thickness to prevent sagging or vibration damage.

Q5: How should pipes be cleaned and maintained?
A5: Routine cleaning can be done with warm water or neutral detergent. Avoid using strong acids or alkalis. Sanitary-grade pipes require periodic cleaning to prevent sediment buildup or microbial growth that could compromise the quality of transported fluids.

Q6: How should pipe quality be inspected after long-term use?
A6: Annual inspection of welds and pipe surfaces is recommended, with ultrasonic or radiographic non-destructive testing as needed. Focus on inspecting welds for cracks, porosity, or corrosion points.

Q7: What issues arise with piping in low-temperature environments?
A7: Austenitic stainless steel pipes retain toughness at low temperatures. However, in extreme cold (-100°C or below) or cold-shock conditions, low-temperature grade materials or Duplex pipes must be selected to ensure safety.

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