SIST EN 10378:2025
(Main)Welded stainless steel square and rectangular tubes for mechanical, engineering and decorative use - Technical delivery conditions
Welded stainless steel square and rectangular tubes for mechanical, engineering and decorative use - Technical delivery conditions
This document specifies the technical delivery conditions for welded tubes, of square and rectangular cross section, made from stainless steels, for mechanical and structural engineering and decorative use.
Geschweißte quadratische und rechteckige Rohre aus nichtrostendem Stahl für den Maschinenbau und dekorative Anwendungen - Technische Lieferbedingungen
Dieses Dokument legt die technischen Lieferbedingungen für geschweißte quadratische und rechteckige Rohre aus nichtrostendem Stahl für den Maschinenbau, für das Bauwesen und für dekorative Anwendungen fest.
Tubes carrés et rectangulaires soudés en acier inoxydable pour usage mécanique, technique et décoratif - Conditions techniques de livraison
Le présent document spécifie les conditions techniques de livraison des tubes soudés, de section transversale carrée et rectangulaire, en acier inoxydable, destinés à la construction mécanique et structurelle et à la décoration.
Varjene kvadratne in pravokotne cevi iz nerjavnega jekla za mehansko, strojno in dekorativno uporabo - Tehnični dobavni pogoji
Ta dokument določa tehnične dobavne pogoje za varjene cevi s kvadratnim in pravokotnim prečnim prerezom iz nerjavnega jekla za mehansko, strojno in dekorativno uporabo.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2025
Varjene kvadratne in pravokotne cevi iz nerjavnega jekla za mehansko, strojno in
dekorativno uporabo - Tehnični dobavni pogoji
Welded stainless steel square and rectangular tubes for mechanical, engineering and
decorative use - Technical delivery conditions
Geschweißte quadratische und rechteckige Rohre aus nichtrostendem Stahl für den
Maschinenbau und dekorative Anwendungen - Technische Lieferbedingungen
Tubes carrés et rectangulaires soudés en acier inoxydable pour usage mécanique,
technique et décoratif - Conditions techniques de livraison
Ta slovenski standard je istoveten z: EN 10378:2025
ICS:
23.040.10 Železne in jeklene cevi Iron and steel pipes
77.140.75 Jeklene cevi in cevni profili Steel pipes and tubes for
za posebne namene specific use
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 10378
EUROPEAN STANDARD
NORME EUROPÉENNE
September 2025
EUROPÄISCHE NORM
ICS 23.040.10
English Version
Welded stainless steel square and rectangular tubes for
mechanical and structural engineering and decorative use
- Technical delivery conditions
Tubes carrés et rectangulaires soudés en acier Geschweißte quadratische und rechteckige Rohre aus
inoxydable pour usage mécanique, technique et nichtrostendem Stahl für den Maschinenbau, für das
décoratif - Conditions techniques de livraison Bauwesen und für dekorative Anwendungen -
Technische Lieferbedingungen
This European Standard was approved by CEN on 20 July 2025.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 10378:2025 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Symbols . 6
5 Classification and designation . 7
5.1 Grades and qualities . 7
5.2 Designation . 7
6 Information to be supplied by the purchaser . 7
6.1 Mandatory information . 7
6.2 Options . 7
6.3 Example of an order . 8
7 Manufacturing process . 8
7.1 Steel making process . 8
7.2 Tube manufacturing process . 8
7.3 Delivery conditions . 8
8 Requirements . 10
8.1 General. 10
8.2 Chemical composition . 10
8.2.1 Cast analysis . 10
8.2.2 Product analysis . 13
8.3 Mechanical properties . 14
8.4 Appearance . 15
8.5 Dimensions. 15
8.5.1 Outside dimensions and wall thickness . 15
8.5.2 Lengths. 15
8.5.3 Mass . 15
8.6 Tolerances . 16
8.6.1 Tolerances on outside dimensions and wall thickness . 16
8.6.2 Tolerances on length . 16
8.6.3 Tolerances on shape . 17
8.6.4 Dimple tolerances . 17
8.7 End preparation . 17
8.8 Sectional properties . 17
9 Inspection and testing . 17
9.1 Types of inspection and testing . 17
9.2 Inspection documents . 18
9.2.1 Types of inspection documents . 18
9.2.2 Content of inspection documents. 18
9.3 Summary of inspection and testing . 19
10 Sampling . 19
10.1 Frequency of tests . 19
10.1.1 Test unit . 19
10.1.2 Number of sample tubes per each test unit. 20
10.2 Preparation of samples and test pieces . 20
10.2.1 General . 20
10.2.2 Test piece for the tensile test at room temperature . 20
10.2.3 Test piece for the flattening test . 20
10.2.4 Test piece for the product analysis . 20
11 Test methods . 21
11.1 Chemical analysis . 21
11.2 Tensile test at room temperature . 21
11.3 Destructive test of weld . 21
11.3.1 Flattening test . 21
11.3.2 Weld bending test . 22
11.4 Dimensional inspection . 23
11.4.1 General . 23
11.4.2 Measurement of size and shape . 23
11.5 Visual examination . 28
11.6 Material identification . 28
11.7 Tensile test at elevated temperature . 28
11.8 Retests, sorting and reprocessing . 28
12 Marking . 28
12.1 Marking to be applied . 28
12.2 Additional marking . 29
13 Handling and packaging . 29
Annex A (informative) Applicable roughness for polished square and rectangular tubes
according to the requested polished grit number (PGN) . 30
Annex B (informative) Formulae for the calculation of sectional properties . 31
European foreword
This document (EN 10378:2025) has been prepared by Technical Committee CEN/TC 459 “ECISS -
European Committee for Iron and Steel Standardization” , the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by March 2026, and conflicting national standards shall be
withdrawn at the latest by March 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Through its sub-committee CEN/TC 459/SC 10 “Steel tubes, and iron and steel fittings” (secretariat: UNI).
1 Scope
This document specifies the technical delivery conditions for welded tubes, of square and rectangular
cross section, made from stainless steels, for mechanical and structural engineering and decorative use.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 10020, Definition and classification of grades of steel
EN 10021, General technical delivery conditions for steel products
EN 10027-1, Designation systems for steels — Part 1: Steel names
EN 10027-2, Designation systems for steels — Part 2: Numerical system
EN 10088-1, Stainless steels — Part 1: List of stainless steels
EN 10168, Steel products — Inspection documents — List of information and description
EN 10204, Metallic products — Types of inspection documents
EN 10266, Steel tubes, fittings and structural hollow sections — Symbols and definitions of terms for use in
product standards
CEN/TR 10261, Iron and steel — European standards for the determination of chemical composition
EN ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical
testing (ISO 377)
EN ISO 2566-2, Steel — Conversion of elongation values — Part 2: Austenitic steels (ISO 2566-2)
EN ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
(ISO 6892-1)
EN ISO 6892-2, Metallic materials — Tensile testing — Part 2: Method of test at elevated temperature
(ISO 6892-2)
EN ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition (ISO 14284)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 10020, EN 10021 and EN 10266
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
4 Symbols
For the purposes of this document, the symbols given in Table 1 apply:
Table 1 — List of symbols
Symbol Description Unit
A Cross-sectional area mm
A Superficial area per metre length m /m
s
A Percentage elongation after fracture %
Specified side dimension of a square tube;
B mm
Specified dimension of the shorter side of a rectangular tube
C /C Length of corner region of a square or rectangular tube mm
1 2
C Torsional modulus constant cm
t
e Deviation from straightness mm
H Specified dimension of the longer side of a rectangular tube. mm
HFIW High frequency induction welding _
I Second moment of area cm
I Torsional inertia constant cm
t
L Original gauge length mm
i Radius of gyration cm
L Length mm
M Mass per unit length kg/m
NDT Non-destructive testing _
R External corner radius of a square or rectangular tube mm
r External corner radius mm
o
R 0,2 % proof strength (yield strength) MPa
p0,2
R Tensile strength MPa
m
ρ Density of stainless steel kg/dm
S Original cross-sectional area of the parallel length mm
T Specified wall thickness mm
Θ Angle between adjacent sides of a square or rectangular tube °
V Total measured twist mm
V Twist measured at one end of a tube mm
W Elastic section modulus cm
el
W Plastic section modulus cm
pl
x Concavity of a side of a square or rectangular tube mm
x Convexity of a side of a square or rectangular tube mm
Symbol Description Unit
yy Axis of cross-section, major axis of a rectangular tube -
zz Axis of cross-section, minor axis of a rectangular tube -
5 Classification and designation
5.1 Grades and qualities
The stainless steels of this document are subdivided in grades on the basis of the chemical composition.
5.2 Designation
For the stainless steel grades covered by this document the steel names shall be allocated in accordance
with EN 10027-1; the steel numbers shall be allocated in accordance with EN 10027-2.
6 Information to be supplied by the purchaser
6.1 Mandatory information
The following information shall be supplied by the purchaser at the time of enquiry and order:
a) the quantity (mass or total length or number);
b) the term “square tube” or “rectangular tube”;
c) the dimensions (outside dimensions B, H and wall thickness T) (see 8.5);
d) the steel designation (see 5.2).
6.2 Options
A number of options are specified in this document and these are listed below with appropriate clause
references. In the event that the purchaser does not indicate a wish to implement any of these options at
the time of enquiry and order, the tube shall be supplied in accordance with the basic specification (see
6.1).
1) delivery condition and/or process route (see 7.3);
2) product analysis for the tube (see 8.2.2);
3) random length (see 8.5.2);
4) exact length (see 8.5.2);
5) type of length, Range of length or Length (see 8.6.2 Table 12);
6) dimple category (see 8.6.4 Table 14);
7) specific inspection and testing (see 9.1 and 9.2.1)
8) inspection certificate “type 3.2” (see 9.2.1);
9) test piece for tensile test shall contain the weld (see 10.2.2);
10) tensile test at elevated temperature (see 11.7);
11) additional marking (see 12.2);
12) special protection (see Clause 13).
6.3 Example of an order
Fifteen tonnes of welded stainless steel square tubes with a specified outside dimensions 20 × 20 mm, a
specified wall thickness of 1,2 mm, in accordance with EN 10378, made from steel grade 1.4301.
15 t – Tube – 20 × 20 × 1,2 - EN 10378 - 1.4301
7 Manufacturing process
7.1 Steel making process
Unless a special steelmaking process is agreed at the time of enquiry and order, the steelmaking process
for stainless steels used for the manufacture of the square and rectangular tubes conforming to this
document shall be at the discretion of the tube manufacturer.
7.2 Tube manufacturing process
Tubes shall be manufactured by a continuous automatic welding process with or without addition of filler
material, starting from hot or cold rolled coils of stainless steel. Tubes manufactured by a continuous
process shall not include the welds used to join the lengths of strip prior to forming the tube. However,
jointers are permitted when the purchaser specifies lengths in excess of the production maximum, if
agreed at the time of enquiry and order.
The admitted welding processes are: automatic arc welding, laser welding, high frequency induction
welding (HFIW). If required, the process route shall be declared by the tube manufacturer. If one specific
process route would be requested, it shall be indicated at the time of enquiry and order (see Option 1).
7.3 Delivery conditions
The tubes will be supplied in the delivery conditions specified in Table 2. Depending on the welding
process the tubes will be supplied with starting material and weld conditions specified in Table 3.
Unless specified at the time of enquiry and order (see Option 1), the selection of the delivery conditions
and process route are at the discretion of the manufacturer.
The cleanness criterion shall be agreed between the customer and the supplier at the time of the enquiry
and order.
Table 2 — Delivery conditions
Symbol Delivery conditions External surface characteristics
Welded tube from hot rolled or cold rolled
a
W0 As welded
strip 1D, 2D, 2E, 2B, 2R
Unless agreed at the time of enquiry and
Welded tube from hot rolled or cold rolled
WG
order the type of brushing shall be at
strip 1D, 2D, 2E, 2B: brushed
b
discretion of the manufacturer
Unless agreed at the time of enquiry and
Welded tube from hot rolled or cold rolled
WP order the type and degree of polishing
strip 1D, 2D, 2E, 2B: polished
shall be at discretion of the manufacturer.
Unless agreed at the time of enquiry and
Welded tube from hot rolled or cold rolled order the type and degree of mirror
WL
strip 1D, 2D, 2E, 2B, 2R: mirror polished polishing shall be at discretion of the
manufacturer.
As welded + after treatment according
Welded tube from hot rolled or cold rolled
WT customer order; surface treatment shall be
strip 1D, 2D, 2E, 2B, 2R: surface treatment
defined at the time of enquiry and order
a
Tubes may have residual scale, welding colours and grease or oil.
b
Tubes may have grease or oil residual.
Table 3 — Tube process route, welding process, starting material, weld conditions
Route Welding process Starting material Weld condition
01 as welded;
external bead brushed
02 Automatic arc Hot or cold rolled
internal bead not rolled
welding strips
external bead brushed internal bead
rolled
04 as welded;
external bead removed
05 HFIW (high frequency Hot or cold rolled
internal bead not removed
induction welding) strips
external bead removed internal bead
removed
07 as welded;
external bead brushed
Hot or cold rolled
Laser welding internal bead not rolled
strips
external bead brushed
internal bead rolled
8 Requirements
8.1 General
Tubes, when supplied in a delivery condition in accordance with 7.3 and inspected in accordance with
Clauses 9, 10 and 11 shall conform to the requirements of this document.
In addition, the general technical delivery requirements specified in EN 10021 shall apply.
8.2 Chemical composition
8.2.1 Cast analysis
The cast analysis reported by the steel manufacturer shall apply and conform to the requirements of
Table 4 for austenitic steel, of Table 5 for austenitic-ferritic steel and Table 6 for ferritic steel.
Tubes with a chemical composition according to EN 10088-1 and not present in Tables 4, 5 and 6 may be
requested and agreed at the time of the enquiry and the order: in this case the mechanical properties
shall be agreed at the time of the enquiry and the order.
When welding tubes produced according to this document, account should be taken of the fact that the
behaviour of the steel during and after welding is dependent not only on the steel, but also on the applied
heat treatment and the conditions of preparing for and carrying out the welding.
Table 4 — Chemical composition (cast analysis) of austenitic corrosion resisting steels
a
Steel designation % by mass
Name Number C Si Mn P S Cr Ni Mo N Cu Others
X2CrNiN18–7 1.4318 0,030 1,00 2,00 0,045 0,015 16,5 to 18,5 6,0 to 8,0 - 0,10 to 0,20 - -
b
X2CrNi18–9 1.4307 0,030 1,00 2,00 0,045 0,015 17,5 to 19,5 8,0 to 10,5 - 0,10 - -
b
X5CrNi18–10 1.4301 0,07 1,00 2,00 0,045 0,015 17,5 to 19,5 8,0 to 10,5 - 0,10 - -
b
X6CrNiTi18–10 1.4541 0,08 1,00 2,00 0,045 0,015 17,0 to 19,0 9,0 to 12,0 - - - Ti: 5 x C to 0,70
b
X2CrNiMo17–12–2 1.4404 0,030 1,00 2,00 0,045 0,015 16,5 to 18,5 10,0 to 13,0 2,00 to 3,00 0,10 - -
b
X5CrNiMo17–12–2 1.4401 0,07 1,00 2,00 0,045 0,015 16,5 to 18,5 10,0 to 13,0 2,00 to 2,50 0,10 - -
b
X6CrNiMoTi17–12–2 1.4571 0,08 1,00 2,00 0,045 0,015 16,5 to 18,5 10,5 to 13,5 2,00 to 2,50 - - Ti: 5 x C to 0,70
b
X2CrNiMo17–12–3 1.4432 0,030 1,00 2,00 0,045 0,015 16,5 to 18,5 10,5 to 13,0 2,50 to 3,00 0,10 - -
b
X2CrNiMoN17–13–5 1.4439 0,030 1,00 2,00 0,045 0,015 16,5 to 18,5 12,5 to 14,5 4,0 to 5,0 0,12 to 0,22 - -
X1NiCrMoCu25–20–5 1.4539 0,020 0,70 2,00 0,030 0,010 19,0 to 21,0 24,0 to 26,0 4,0 to 5,0 0,15 1,20 to 2,00 -
5,5 to -
X12CrMnNiN17–7–5 1.4372 0,15 1,00 0,045 0,015 16,0 to 18,0 3,5 to 5,5 - 0,050 to 0,25 -
7,5
b
X3CrNiMo17–13–3 1.4436 0,05 1,00 2,00 0,045 0,015 16,5 to 18,5 10,5 to 13,0 2,50 to 3,00 0,10 - -
X1CrNiMoCuN20–18–7 1.4547 0,020 0,70 1,00 0,030 0,010 19,5 to 20,5 17,5 to 18,5 6,0 to 7,0 0,18 to 0,25 0,50 to 1,00 -
Elements not quoted (“-”) or not listed in this table shall not be intentionally added to the steel without the agreement of the purchaser except for finishing the cast. All appropriate
precautions shall be taken to avoid the addition of such elements from scrap and other materials used in production which would impair mechanical properties and the suitability
of the steel.
a
Maximum values unless indicated otherwise
b
Particular ranges of sulfur content may provide improvement of particular properties. For machinability a controlled sulfur content of 0,015 % to 0,030 % is recommended
and permitted. For weldability, a controlled sulfur content of 0,008 % to 0,015 % is recommended and permitted. For polishability, a controlled sulfur content of 0,015 % max.
is recommended.
Table 5 — Chemical composition (cast analysis) of austenitic-ferritic corrosion resisting steels
a
Steel designation % by mass
Name Number C Si Mn P S Cr Ni Mo N Cu Others
X2CrNiN23–4 1.4362 0,030 1,00 2,00 0,035 0,015 22,0 to 24,5 3,5 to 5,5 0,10 to 0,60 0,050 to 0,20 0,10 to 0,60 -
b b
X2CrNiMoN22–5–3 1.4462 0,030 1,00 2,00 0,035 0,015 21,0 to 23,0 4,5 to 6,5 2,50 to 3,5 0,10 to 0,22 - -
c c
X2CrNiN22–2 1.4062 0,030 1,00 2,00 0,040 0,010 21,5 to 24,0 1,00 to 2,90 0,45 0,16 to 0,28 - -
X2CrMnNiN21–5–1 1.4162 0,040 1,00 4,0 to 6,0 0,040 0,015 21,0 to 22,0 1,35 to 1,90 0,10 to 0,80 0,20 to 0,25 0,10 to 0,80 -
c c
X2CrNiMnMoCuN24–4–3–2 1.4662 0,030 0,70 2,50 to 4,0 0,035 0,005 23,0 to 25,0 3,00 to 4,5 1,00 to 2,00 0,20 to 0,30 0,10 to 0,80 -
Elements not quoted (“-”) or not listed in this table shall not be intentionally added to the steel without the agreement of the purchaser except for finishing the cast. All appropriate precautions
shall be taken to avoid the addition of such elements from scrap and other materials used in production which would impair mechanical properties and the suitability of the steel.
a
Maximum values unless indicated otherwise
b
By agreement, this grade can be delivered with a Pitting Resistance Equivalent Number (PRE = Cr + 3,3 Mo + 16 N, compare Table D.1 of EN 10088-1) greater than 34.
c
Patented steel grade
Table 6 — Chemical composition (cast analysis) of ferritic corrosion resisting steels
a
Steel designation % by mass
C Si Mn P S Cr Ni Mo N Nb Ti Other
Name Number
s
X2CrNi12 1.4003 0,030 1,00 2,00 0,040 0,015 10,5 to 12,5 0,30 to 1,00 - 0,030 - - -
c
X2CrTi12 1.4512 0,030 1,00 1,00 0,040 0,015 10,5 to 12,5 - - - - [6x (C+N)] to 0,65 -
b c
X3CrTi17 1.4510 0,05 1,00 1,00 0,040 0,015 16,0 to 18,0 - - - - [4x(C+N) + 0,15] to 0,80 -
c
X2CrMoTi18–2 1.4521 0,025 1,00 1,00 0,040 0,015 17,0 to 20,0 - 1,75 to 2,50 0,030 - [4x(C+N) + 0,15] to 0,80 -
X2CrTiNb18 1.4509 0,030 1,00 1,00 0,040 0,015 17,5 to 18,5 - - - [3xC+0,30] to 1,00 0,10 to 0,60 -
Elements not quoted (“-”) or not list
...
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