SIST EN 10336:2007

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Continuously hot-dip coated and electrolytically coated strip and sheet of multiphase steels for cold forming - Technical delivery conditionBandes et tôles en aciers multiphasés revetus en continu par immersion a chaud et revetus par voie électrolytique pour formage a froid - Conditions techniques de livraisonKontinuierlich schmelztauchveredeltes und elektrolytisch veredeltes Band und Blech aus Mehrphasenstählen zum Kaltumformen - Technische LieferbedingungenTa slovenski standard je istoveten z:EN 10336:2007SIST EN 10336:2007en77.140.50SROL]GHONLFlat steel products and semi-productsICS:SLOVENSKI
STANDARDSIST EN 10336:200701-junij-2007







EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 10336April 2007ICS 77.140.50 English VersionContinuously hot-dip coated and electrolytically coated strip andsheet of multiphase steels for cold forming - Technical deliveryconditionsBandes et tôles en aciers multiphasés revêtus en continupar immersion à chaud et revêtus par voie électrolytiquepour formage à froid - Conditions techniques de livraisonKontinuierlich schmelztauchveredeltes und elektrolytischveredeltes Band und Blech aus Mehrphasenstählen zumKaltumformen - Technische LieferbedingungenThis European Standard was approved by CEN on 15 March 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2007 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 10336:2007: E



EN 10336:2007 (E) 2
Contents page Foreword.3 1 Scope.4 2 Normative references.4 3 Terms and definitions.5 4 Classification and designation.6 4.1 Classification.6 4.2 Designation.6 5 Information to be supplied by the purchaser.6 5.1 Mandatory information.6 5.2 Options.7 6 Manufacturing process.8 7 Requirements.8 7.1 Chemical composition.8 7.2 Mechanical properties.11 7.3 Requirements for coatings.12 7.4 Tolerances on dimensions and shape.18 7.5 Suitability for further processing.18 8 Testing.18 8.1 General.18 8.2 Test units.19 8.3 Number of tests.19 8.4 Sampling.19 8.5 Test methods.20 8.6 Retests.20 8.7 Inspection documents.20 9 Marking.20 10 Packing.21 11 Storage and transportation.21 12 Disputes.21 Annex A (normative)
Reference method for determination of the zinc coating mass.22 Annex B (normative)
Reference method for determination of the zinc-nickel coating mass and the zinc-nickel coating composition for electrolytically coated products.23 Bibliography.25



EN 10336:2007 (E) 3
Foreword This document (EN 10336:2007) has been prepared by Technical Committee ECISS/TC 27 “Surface coated flat products - Qualities, dimensions, tolerances and specific tests”, the secretariat of which is held by DIN. 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 October 2007, and conflicting national standards shall be withdrawn at the latest by October 2007. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard : Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.



EN 10336:2007 (E) 4
1 Scope 1.1
This European Standard specifies requirements for continuously hot-dip coated and electrolytically coated flat products made of multiphase steels for cold forming (see Table 1, Table 3 and Table 4) coated with zinc (Z and ZE), zinc-iron alloy (ZF) or zinc-nickel alloy (ZN) with thicknesses of 0,35 mm to 3,0 mm, unless otherwise agreed (see 1.2).
The thickness is the final thickness of the delivered product after coating. This European Standard applies to strip of a width ≥ 600 mm and sheets cut from it.
1.2 If agreed at the time of enquiry and order, this European Standard may also be applied to continuously hot-dip coated flat products of thicknesses > 3,0 mm. In this case the mechanical property, adhesion of the coating and surface condition requirements should also be agreed at the time of enquiry and order. 1.3
The products covered by this European Standard are mainly used where cold formability, high strength and corrosion resistance are the most important factors. Corrosion resistance of the coating is proportional to the coating mass (see also 7.3.5) 1.4
This European Standard is not applicable to: • continuously hot dip coated steel flat products made of low carbon steels (see EN 10327); • continuously hot-dip coated structural steel flat products (see EN 10326); • electrolytically zinc coated cold rolled steel flat products (see EN 10152); • continuously organic coated (coil coated) steel flat products (see EN 10169-1, EN 10169-2 and
EN 10169-3); • electrolytically zinc-nickel coated cold rolled steel flat products (see EN 10271); and • continuously hot-dip coated strip and sheet of steels with high yield strength for cold forming
(see EN 10292). 2 Normative references The following referenced documents are indispensable for the application 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 10002-1:2001, Metallic materials – Tensile testing – Part 1: Method of test at ambient temperature EN 10020:2000, Definition and classification of grades of steel EN 10021:2006, 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 10079:2007, Definition of steel products EN 10131, Cold rolled uncoated and zinc or zinc-nickel electrolytically coated low carbon and high yield strength steel flat products for cold forming - Tolerances on dimensions and shape EN 10143, Continuously hot-dip coated steel sheet and strip – Tolerances on dimensions and shape EN 10204:2004, Metallic products – Types of inspection documents EN 10325, Steel – Determination of yield strength increase by the effect of heat treatment (Bake-Hardening-Index) ISO 10275, Metallic materials – Sheet and strip – Determination of tensile strain hardening exponent



EN 10336:2007 (E) 5
3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 10020:2000, EN 10021:2006,
EN 10079:2007, EN 10204:2004 and the following apply. NOTE General definitions and guidelines for the protection of iron and steel can be found in EN ISO 14713. 3.1 hot-dip zinc coating (Z) application of a zinc coating by immersing the prepared products in a molten bath containing a zinc content of at least 99 % (see also 7.3.2.2) 3.2 hot-dip zinc-iron coating (ZF) application of a zinc coating by immersing the prepared products in a molten bath containing a zinc content of at least 99 %; subsequent annealing produces an iron-zinc coating with an iron content of normally 8 % to 12 % (see also 7.3.2.3) 3.3 electrolytic zinc coating (ZE)
application of a zinc coating by electrolysis on a suitably prepared steel surface from an aqueous salt solution by the use of an electric current 3.4 electrolytic zinc-nickel coating (ZN) application of a zinc nickel coating by electrolysis on a suitably prepared steel surface from an aqueous salt solution by the use of an electric current NOTE Flat products may have a zinc or zinc-nickel coating on one or both surfaces. If both surfaces are coated, a different coating thickness may be applied on each side (this process is referred to as differential zinc or zinc-nickel coating). 3.5 FB (ferritic-bainitic) steel steel containing, independent of the rolling process, bainite or strengthened bainite in a matrix consisting of ferrite and/or strengthened ferrite
NOTE The strengthening of the matrix is caused by a high density of dislocations, by grain refinement and precipitation of micro-alloying elements 3.6 DP (dual-phase) steel steel with a ferritic matrix containing a martensitic second phase present in the form of islands and eventually bainite as a complementary phase
NOTE According to their high tensile strength levels, dual phase steels show a low yield strength ratio and a high work hardening rate 3.7 TRIP (transformation induced plasticity) steel steel with a mainly ferritic matrix containing retained austenite which can transform to martensite (TRIP effect) during the forming process NOTE Due to its high work-hardening rate the steel reaches high uniform elongation values and high tensile strength levels 3.8 CP (complex-phase) steel steel with a ferrite/bainite matrix containing small amounts of martensite, retained austenite and or pearlite NOTE An extreme grain refinement is caused by retarded recrystallisation or precipitation of micro-alloying elements



EN 10336:2007 (E) 6
3.9 MS (martensitic) steel steel with a martensitic matrix containing small amounts of ferrite and/or bainite produced by thermomechanical rolling
NOTE Within the group of multiphase steels the MS steels show the highest tensile strength level 3.10 coating mass total mass of coating (expressed in grams per square metre) given for both surfaces in the case of Z or ZF coating and separately for each surface in the case of ZE or ZN coating (see 7.3.5)
NOTE The nominal coating mass is used as coating designation in the case of hot dip coated products (Z, ZF). For electrolytically coated products (ZE, ZN), the coating thickness is used for coating designation. 4 Classification and designation 4.1 Classification The steel grades covered by this standard are alloy quality steels in accordance with EN 10020. They are classified in accordance with their increasing minimum tensile strength (Rm) (see Table 1, Table 3 and Table 4). 4.2 Designation 4.2.1 Steel names For the steel grades covered by this standard, the steel names are allocated in accordance with EN 10027-1. 4.2.2 Steel numbers For the steel grades covered by this standard, the steel numbers are allocated in accordance with EN 10027-2. 5 Information to be supplied by the purchaser 5.1 Mandatory information The following information shall be supplied by the purchaser at the time of enquiry and order: a) quantity to be delivered; b) type of product (strip, sheet, cut length); c) number of the dimensional standard (EN 10143 or EN 10131 – see 7.4); d)
nominal dimensions and the tolerances on dimensions and shape and, if applicable, letters denoting
relevant special tolerances; e)
term "steel"; f)
number of this European Standard, i. e. EN 10336; g)
steel name or steel number and symbol for the type of coating as given in Table 1; h) number designating the nominal mass of coating for Z, ZF (e.g. 275 = 275 g/m² including both surfaces) or the nominal coating thickness for ZE, ZN (e.g. ZN 50/20 = 5,0 µm thickness on one side, 2,0 µm thickness on the other side) (see Table 5 through Table 9 ); i) letter denoting the coating finish of hot dip coated products (N, M or R, see 7.3.2 and Table 5 and Table 6); j) letter denoting the surface quality (A, B or C, see 7.3.3.2; or A or B, see 7.3.3.3); k) letter(s) denoting the surface treatment (C, O, CO, P or S for hot dip coated products and C, O, CO, P, S, PC, PCO or PO for electrolytically coated products, see 7.3.4.1).



EN 10336:2007 (E) 7
EXAMPLE 1: 1 sheet, delivered with dimensional tolerances in accordance with EN 10143 with a nominal thickness of 0,80 mm, ordered with special thickness tolerances (S), with a nominal width of 1 200 mm, ordered with special width tolerances (S), with a nominal length of 2 500 mm, ordered with special flatness tolerances (FS), made of steel HCT600X in accordance with EN 10336, hot dip zinc-iron coated, coating mass 100 g/m² (100), coating finish R, surface quality B, surface treatment oiled (O):
1 sheet EN 10143–0,80Sx1200Sx2500FS–steel EN 10336–HCT600X+ZF100–R–B–O
or
1 sheet EN 10143–0,80Sx1200Sx2500FS–steel EN 10336–1.0941+ZF100–R–B–O
EXAMPLE 2: Strip delivered with dimensional tolerances in accordance with EN 10131, with nominal thickness of 1,20 mm, nominal
width of 1 500 mm, made of steel HCT780C in accordance with EN 10336, electrolytically zinc coated with a nominal thickness of 5 µm on both surfaces (50/50), surface quality A, surface treatment phosphated (P):
Strip EN 10131–1,20x1500–steel EN 10336–HCT780C+ZE50/50–A–P
or
Strip EN 10131–1,20x1500–steel EN 10336–1.0954+ZE50/50–A–P 5.2 Options A number of options are specified in this standard and listed below. lf the purchaser does not indicate his/her wish to implement one of these options, the products shall be supplied in accordance with the basis specification of this standard (see 5.1). a) Specification of product thicknesses deviating from those given in the scope (see 1.2); b) verification of the product analysis (see 7.1.2); c) specification of the values in Table 3 and Table 4 for longitudinal instead of transverse test pieces (see 7.2.2); d) coating masses different from those in Table 7 to Table 9 (see 7.3.1.2); e) different coating masses on each surface (see 7.3.1.3); f) products with pronounced spangle (see 7.3.2.2.a)); g) requirement on surface roughness (see 7.3.3.4); h) inspection of both surfaces or notification of which surface has been inspected (see 7.3.3.5.a)); i) maximum or minimum value for the coating mass per product surface (see 7.3.5.1); j) one side coating with specified rest coating mass on the uncoated surface (see 7.3.5.2.e)); k) specification of tolerances, other than those of EN 10131 for electrolytically coated products and those of EN 10143 for hot-dip coated products (see 7.4); l) maximum value for the coating mass per surface (see 7.3.5.2.f)); m) testing for compliance with the requirements of this standard (see 8.1.1 and 8.1.2); n) supply of an inspection document and type of document (see 8.7); o) marking desired by branding of the products (see 9.2); p) requirements for packing (see Clause 10).



EN 10336:2007 (E) 8
6 Manufacturing process The processes used in steelmaking and manufacture of the products are left to the discretion of the manufacturer. 7 Requirements 7.1 Chemical composition 7.1.1 The chemical composition according to the cast analysis shall be as specified in Table 1. 7.1.2 If a product analysis is agreed at the time of enquiry and order, the permitted deviations from the cast analysis given in Table 1 shall meet the requirements in Table 2.



EN 10336:2007 (E) 9
Table 1 — Chemical composition (cast analysis)
Steel designation % by mass Steel grade Steel namea Steel number
Symbols for the types of available coatings
C max.
Si max.
Mn max.
P max.
S max.
Altotal
Cr+Momax.
Nb+Ti max.
V max.
B max. FB steels HDT450F 1.0961 0,18 0,50
1,20 0,030
0,010 ≥ 0,015
0,30 0,05 0,15 0,005 HDT560F 1.0959 +Z, +ZF, +ZE, +ZN 0,18 0,50
1,80 0,025 0,010 ≥ 0,015
0,30 0,15 0,15 0,005 DP steels HCT450X 1.0937 HCT500X 1.0939 0,14 2,00 HCT600X 1.0941 HDT580X 1.0936 0,17 2,20 HCT780X 1.0943 0,18 HCT980X 1.0944
+Z, +ZF, +ZE, +ZN 0,23
0,80 2,50
0,080
0,015
≤ 2,00
1,00
0,15
0,20
0,005 TRIP steels HCT690T 1.0947 HCT780T 1.0948 +Z, +ZF, +ZE, +ZN 0,32 2,20 2,50 0,12 0,015 ≤ 2,00 0,60 0,20 0,20 0,005 CP steels HCT600C 1.0953 HDT750C 1.0956 HCT780C 1.0954 HDT780C 1.0957 0,18
1,00
HDT950C 1.0958
0,20 HCT980C 1.0955
+Z , +ZF, +ZE, +ZN 0,23 0,80 2,20
0,080
0,015
≤ 2,00 1,20
0,15 0,22
0,005



EN 10336:2007 (E) 10
Table 1 (continued) Steel designation % by mass Steel grade Steel namea Steel number
Symbols for the types of available coatings
C max.
Si max.
Mn max.
P max.
S max.
Altotal max.
Cr+Momax.
Nb+Ti max.
V max.
B max. MS steels HDT1200M 1.0965 +Z , +ZF, +ZE, +ZN 0,25 0,80 2,00 0,060 0,015 ≤ 2,00 1,20 0,15 0,22 0,005 a
H
flat products of high strength for cold forming; C
cold rolled products; D
hot rolled products;
T(n)nnn
minimum tensile strength Rm (rounded up) in MPa. Last symbol of the steel name: F ferritic-bainitic steel; X dual phase steel; T TRIP steel; C Complex phase steel; M
martensitic steel.
Table 2 — Permissible deviations of the product analysis from specified limits
on cast analysis given in Table 1 Element Specified limit of the cast analysis in Table 1 % by mass Permissible deviation of the product analysis % by mass C ≤ 0,32 + 0,02 ≤ 0,80 + 0,05
Si > 0,80
≤ 2,20 + 0,10 Mn ≤ 2,50 + 0,10 P ≤ 0,12 + 0,01 S ≤ 0,015 + 0,003 Altotal ≤ 2,00 + 0,10 Cr+Mo ≤ 1,20 + 0,05 Nb+Ti ≤ 0,20 + 0,02 V ≤ 0,22 + 0,02 B ≤ 0,005 + 0,001



EN 10336:2007 (E) 11 7.2 Mechanical properties 7.2.1 The mechanical properties of the products shall comply with the requirements in Table 3 or Table 4. 7.2.2 The values for the tensile test apply for transverse pieces and shall be referred to the test piece cross section without coating. Alternatively, by agreement at the time of enquiry and order, the values in Table 3 and Table 4 shall apply for longitudinal test pieces instead of transverse test pieces, but not both at the same time. 7.2.3 The strain hardening exponent n shall be in the range of homogeneous deformation, within the strain range of 10 % to 20 %.
NOTE The uniform elongation of the material tested may be lower than 20 %. In this case, an upper limit of the strain range of
≥ 15 % may be applied. Table 3 — Mechanical properties (cold rolled products) Steel grade
Steel name Steel number Proof strength Rp0,2
MPa
Tensile strength Rm
MPa
min. Elongation A80 a,b
%
min. Strain harde-ning exponent n10-UE min. Bake-Harde-ning Index BH2
MPa
min. DP steels HCT450X 1.0937 260 to 340 450 27 0,16 30 HCT500X 1.0939 300 to 380 500 23 0,15 30 HCT600X 1.0941 340 to 420 600 20 0,14 30 HCT780X 1.0943 450 to 560 780 14 – 30 HCT980X 1.0944 600 to 750 980 10 – 30 TRIP steels
HCT690T
1.0947 430 to 550 690 23 0,18 40 HCT780T
1.0948 470 to 600 780
21
0,16 40 CP steels HCT600C 1.0953 350 to 500 600 16 – 30 HCT780C 1.0954 500 to 700 780 10 – 30 HCT980C 1.0955
700 to 900 980 7 – 30 a
Decreased minimum elongation values apply for product thicknesses t ≤ 0,5 mm (minus 4 units) and for 0,5 mm < t
≤ 0,7 mm (minus 2 units) b For ZF-coatings, minimum elongation values lowered by 2 units apply



EN 10336:2007 (E)
12 Table 4 — Mechanical properties (hot rolled products) Steel grade
Steel name Steel number Proof strength
Rp0,2
MPa
Tensile strength Rm
MPa
min. Elongation
A80
%
min. Strain harde-ning exponent n10-UE min. Bake-Harde-ning Index
BH2
MPa
min. FB steels HDT450F 1.0961 320 to 420 450 23 – 30 HDT560F 1.0959 460 to 570 560 16 – 30 DP steels HDT580X 1.0936 330 to 460 580 19 0,13 30 CP steels HDT750C 1.0956 620 to 760 750 10 – 30 HDT780C 1.0957 680 to 830 780 10 – 30 HDT950C 1.0958 720 to 920 950 9 – 30 MS steels HDT1200M 1.0965 900 to 1 150 1 200 5 – 30
7.3
Requirements for coatings 7.3.1 Types of coatings
7.3.1.1 The products shall be supplied with coatings of zinc (Z or ZE) or zinc-iron-alloy (ZF) or zinc-nickel alloy (ZN) as given in Table 5 to Table 9. 7.3.1.2 The available coating masses are given in Table 7 to Table 9. Different coating masses must be especially agreed at the time of enquiry and order. Thicker coatings may limit the formability and weldability of the products. Therefore, the forming and weldability requirements must be taken into account when ordering the coating mass. 7.3.1.3 If agreed at the time of enquiry and order, different coating masses on each surface may be supplied for the hot-dip and electrolytically coated flat products. The two surfaces may have a different appearance as a result of the manufacturing process.



EN 10336:2007 (E)
13Table 5 — Available coatings, finishes and surface qualities for hot dip zinc coatings (Z) Coating finish N
M
Coating designationa Surface qualitya
A A B C Z100 X X X X Z140 X X X X Z200 X X X X (Z225) (X) (X) (X) (X) (Z275) (X) (X) (X) (X) a The coatings and surface qualities given in brackets are available on agreement.
Table 6 — Available coatings, finishes and surface qualities for hot dip zinc-iron alloy coatings (ZF) Coating finish R Coating designation
Surface quality
A B C ZF100 X X X ZF120 X X X Table 7 — Available coating masses for hot dip zinc (Z) and zinc-iron alloy (ZF) coatings Minimum total coating massa, (both surfaces) g/m2 Theoretical guidance values for coating thickness per surface in the single spot test
µm Coating designation Triple spot test Single spot test Average
valueb
(about) Scatter areac Density
g/cm3 Zinc coating masses (Z) Z100 100 85 7 5 to 12 Z140 140 120 10 7 to 15 Z200 200 170 14 11 to 20 Z225 225 195 16 11 to 22 Z275 275 235 20 15 to 27
7,1 Zinc-iron coating masses (ZF) ZF100 100 85 7 5 to 12 ZF120 120 100 8 6 to 13 7,1 a
See 8.5.4. b
Coating thicknesses can be calculated from the coating masses (see 7.3.5.1). c
The user can expect that these limiting values are obtained on the upper surface and on the reverse surface.



EN 10336:2007 (E)
14 Table 8 — Thickness and mass of electrolytical zinc (ZE) coatings
(see also 7.3.5.2)
Nominal zinc coating values for each surfacea Minimum zinc coating values for each surfaceb Coating designation Thickness µm Mass g/m² Thickness µm Mass g/m² ZE25/25 2,5 18 1,7 12 ZE50/50 5,0 36 4,1 29 ZE75/75 7,5 54 6,6 47 ZE100/100 10,0 72 9,1 65 a
A coating mass of 50 g/m² corresponds to a coating thickness of approximately 7,1 µm.
b
See 7.3.5.2.d).
Table 9 — Thickness and mass of electrolytical zinc-nickel (ZN) coatings (see also 7.3.5.2) Nominal zinc-nickel coating values for each surfacea,b Minimum zinc-nickel coating values for each surfacea,b Coating designation Thickness µm Mass g/m² Thickness µm Mass g/m² ZN20/20 2 15 1,5 11 ZN30/30 3 22 2,4 18 ZN40/40 4 29 3,2 23 ZN50/50 5 37 4,1 30 ZN60/60 6 44 5,2 38 a
A coating thickness of 1 µm corresponds to a coating mass of approximately 7,3 g/m². b
See 7.3.5.2.d).
7.3.2 Coating finish (hot dip coated products only)
7.3.2.1 General Depending on the galvanizing conditions, crystals of different sizes and brightness arise. The coating properties are not affected by this. 7.3.2.2 Zinc hot dip coated products (Z) (see Table 5 and Table 7) a) Normal finish (N) The finish is obtained when the zinc coating is left to solidify normally. Either no spangle or zinc crystals of different sizes and brightness appear depending on the galvanizing conditions. The quality of the coating is not affected by this. lf a pronounced spangle is desired, this shall be indicated specially at the time of enquiry and order.



EN 10336:2007 (E)
15b) Minimized spangle (M) The finish is obtained by influencing the solidification process in a specific way. The surface will have reduced spangles, in some cases, not visible to the unaided eye. The finish may be ordered if the normal spangle (see 7.3.2.2.a)) does not satisfy the surface appearance requirements. 7.3.2.3 Zinc-iron alloy hot dip coated products (ZF) (see Table 6 and Table 7) The regular zinc-iron alloy coating (R) results from heat treatment in which iron diffuses through the zinc. The surface has a uniform matt grey appearance.
7.3.3 Surface quality 7.3.3.1 General The product surface shall comply with requirements in 7.3.3.2 or 7.3.3.3 for the ordered surface quality. When supplying strip in coils, there is greater risk of surface defects than if sheet and cut lengths are supplied, as it is not possible for the manufacturer to eliminate all the defects in a coil. This shall be taken into account by the purchaser when evaluating the products. 7.3.3.2 Hot dip coated products The products shall be delivered with surface quality A or B or C as specified. a) As coated surface (A) Imperfections such as small pits, variations in surface appearance, dark spots, stripe marks and light passivation stains are permissible. Stretch levelling breaks or run-off marks may appear. Coil breaks and stretcher strains may appear as well. b) Improved surface (B) Surface quality B is obtained by skin passing. With this surface quality, small imperfections such as stretch levelling breaks, skin pass marks, light scratches, surface structure, run-off marks and light passivation stains are permissible. c) Best quality surface (C) Surface quality C is obtained by skin passing. The better surface shall not impair the uniform appearance of a high-class paint finish. The other surface shall have at least the characteristics of surface quality B (see 7.3.3.2.b)). 7.3.3.3
Electrolytically coated products The products shall be supplied with the surface qualities A or B as specified. a) Surface quality A Imperfections such as slight indentations, small marks, minor scratches and slight
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