GB/T 713.7 06Cr13Al S11348 Pressure Vessel Stainless Plate

06Cr13Al S11348 is listed in GB/T 713.7-2023, the Chinese standard for pressure equipment stainless steel plate, as a nickel-free ferritic grade. As a GB/T 713.7-2023 stainless plate it is ordered by vessel and heat-exchanger shops that design to GB/T 150 and the TSG 21 safety rules, and by EPC contractors who must deliver Chinese-code equipment abroad. Its ASTM A240 405 equivalent is the nearest foreign grade by chemistry.

Reading the designation: the leading digits give the carbon level (≤ 0.08%); the element symbols that follow give the approximate contents of the main alloying elements in percent. S11348 is the unified numeric code (ISC). The grade was previously certified as GB/T 24511 S11348 until GB/T 24511-2017 was withdrawn on 1 March 2024; most chemistries carried over, but the 2023 edition revised some austenitic strength values and added impact data, so old certificates should be checked against the new tables. Older Chinese drawings may still use the former designation 0Cr13Al. Every 06Cr13Al pressure vessel plate is tested and certified to the 2023 edition.

SHH STEEL produces and exports stainless plate from Shanghai, works as a sales agent for mills including TISCO, Baosteel and POSCO, and runs its own processing warehouse for cutting and polishing. 06Cr13Al is part of our GB/T 713.7-2023 pressure vessel stainless plate range; for the general-purpose version of the same grade see GB/T 4237 06Cr13Al S11348.

Why designers specify S11348

Material selection for a Chinese-code pressure vessel starts with the design conditions: medium, temperature, pressure and the minimum design metal temperature. Ferritic grades are chosen when chloride stress-corrosion cracking rules out austenitic steel and when the service temperature keeps the material well above its transition range. GB/T 150 lists the permitted plate standards and allowable stresses, and the material must be supplied with a certificate that ties every plate to its heat. Because 06Cr13Al is listed in GB/T 713.7-2023, it can be used directly under GB/T 150 without a separate material evaluation, which saves time on approvals compared with a foreign grade.

Who buys it

Our customers for this grade include pressure vessel fabricators in China and Southeast Asia, EPC contractors building Chinese-designed plants in the Middle East, Africa and Central Asia, and maintenance teams that need like-for-like replacement plate for equipment originally built to GB/T 24511 or GB/T 713.7. Export buyers often need the plate certified to GB/T 713.7 and checked against an ASTM or EN grade at the same time, which we arrange with the mill before rolling.

The table is a summary; the purchase order should cite the full standard and edition. Clause 4.2 of GB/T 713.7 requires the surface finish to be named on the order, and the edge and thickness-accuracy codes decide the tolerance class used for acceptance. For coil-cut plate, flatness and camber follow the general rules of GB/T 713.1, which every part of GB/T 713 refers to.

The S11348 chemical composition is the heat (melting) analysis the mill reports for each heat, and it must meet GB/T 713.7-2023 Table 15 in weight percent.

The product analysis is a check on the finished plate. Clause 7.2.2 of GB/T 713.7 refers to GB/T 713.1 for the permitted deviations; the values below are the customary GB/T 222 / ASTM A480 deviations applied to 06Cr13Al and should be confirmed against the edition cited in the contract.

PREN (Cr + 3.3Mo + 16N) calculated from the minimum chemistry is 11.5. Notes to the table state that compositions were adjusted compared with GB/T 3280 and GB/T 4237, so a general-purpose certificate does not automatically meet GB/T 713.7.

Product (check) analysis is the chemistry measured on a sample taken from the finished plate rather than from the ladle, and it is how a buyer proves the plate matches the certificate.

Under GB/T 713.7 the mill reports the heat analysis as standard. A product analysis is made when the purchase order calls for it, and the result is judged against the heat limits widened by the permitted deviations shown above. Deviations apply to one side of a range only; a heat may not exceed both the lower and upper limit of the same element. Elements marked ‘by agreement’ have no tabulated deviation and should be settled in the contract.

SHH STEEL runs positive material identification (PMI) on every plate in our Shanghai warehouse before it ships. PMI by handheld XRF confirms Cr, Ni and other alloying elements; it cannot measure carbon or nitrogen, so when low carbon matters we arrange laboratory spark-OES or combustion analysis through our steel testing service. Product analysis results are added to the 3.1 certificate or reported by the third-party inspector on a 3.2 certificate.

Sampling and acceptance

Samples for product analysis are taken across the thickness or from millings so that the result represents the whole plate, not only the surface. If a product analysis falls outside the permitted range, the usual practice under GB/T 713.1 is to retest on additional samples before the plate or batch is rejected. We keep retained samples from tested heats for a period agreed with the customer, which helps when questions arise during fabrication or inspection.

The S11348 mechanical properties are the room-temperature values that GB/T 713.7-2023 Table 18 sets for annealed plate.

Elongation for thickness ≤ 3.00 mm is measured on A50 mm specimens per GB/T 228.1 P5. Design stresses are not taken from this table directly: the vessel designer uses the allowable-stress tables of GB/T 150.2, which are derived from these minimums and from the elevated-temperature data in Annex D where given.

Compared with ASTM A240 405, GB/T 713.7 sets its own strength and elongation minimums; a heat can often be dual-certified, but each certificate must state the values tested against each standard.

How designers use these values

The room-temperature minimums are the basis of the allowable stresses in GB/T 150.2. The designer takes the lower of the stress derived from tensile strength and the stress derived from proof strength, applies the code safety factors, and for elevated temperatures uses the temperature-dependent proof strength. For ferritic grades the allowable stress is moderate and the code temperature limits are narrower than for austenitic grades. Hardness limits on the certificate are a quick check that the plate has been correctly heat treated: a plate above the maximum hardness has usually been under-treated or cold worked.

Testing frequency

Tensile and hardness tests are made per batch as defined in the inspection rules of GB/T 713.7 clause 9 and GB/T 713.1. A batch is plate from the same heat, the same thickness and the same heat-treatment condition. When the order calls for testing of each plate or each rolled plate, state this explicitly, as it affects cost and lead time.

S11348 heat treatment annealing is the final heat treatment that sets the structure and properties of the plate, and GB/T 713.7-2023 Annex C gives the recommended regime for 06Cr13Al. Mills typically anneal this grade at about 780 – 1 000 °C depending on grade followed by air or rapid cooling to give a soft, fully ferritic structure. The actual temperature and cooling method are recorded on the mill certificate.

Clause 7.1.2 allows hot-rolled strip 14.0 – 25.0 mm thick to be levelled and heat treated sheet by sheet. After heavy cold forming or hot forming of heads, the fabricator should follow GB/T 150.4 on whether re-treatment is needed; ferritic plate is normally re-annealed, not quenched.

What can go wrong

An incorrectly heat-treated plate shows up as high hardness, low elongation or, in corrosion tests, as intergranular attack. Over-heating coarsens the ferrite grain and reduces toughness, so annealing temperature and time are controlled closely. When we receive plate, our engineers check the heat-treatment record on the certificate against Annex C and the hardness result before releasing the material.

Toughness is the main design limit for ferritic 06Cr13Al: like other ferritic stainless steels it has a ductile-to-brittle transition, and the transition moves to higher temperatures as thickness increases.

For low-temperature or impact-critical parts, an austenitic grade is the safer choice.

Design checklist for this service

• Confirm the minimum and maximum design metal temperatures against the limits in GB/T 150 for this material.
• State on the order every test that the design relies on, because tests that are ‘by agreement’ are not performed unless they are written into the contract.
• Check that weld procedures, filler metals and any post-weld treatment are qualified for the same temperature range as the base metal.
• Keep the mill certificate, the inspection report and the weld records together in the vessel data book, as required for registration with the special-equipment authority.

A 06Cr13Al equivalent grade is a grade in another standard with similar chemistry and properties, not an interchangeable certificate.

Equivalence is by alloy family, not certificate. Replacing S11348 with a foreign grade in a Chinese-code vessel needs approval from the designer and, where required, the special-equipment inspection authority; the reverse also applies to ASME or PED equipment built from GB/T plate.

Welding of 06Cr13Al is done by GTAW, SMAW, GMAW or SAW with ferritic matching or austenitic 309L-type filler metal. Preheat is generally not needed for thin sections, but heat input should be kept low to limit grain growth in the heat-affected zone. Pickle and passivate welds for corrosive service.

Weld procedures are qualified to NB/T 47014 for Chinese-code equipment, or to ASME IX for export projects. Cold forming of heads and shells is normal for this grade; ferritic plate forms well at room temperature in thin gauges; warm forming may help in heavier sheet. Plasma, laser and waterjet cutting are all suitable; remove heat-tinted edges before welding.

Practical welding notes

• Clean the joint area with stainless-only brushes and solvent; carbon steel contamination causes rust spots.
• Keep heat input low and avoid multiple re-heating of the HAZ.
• Austenitic filler can be used for dissimilar joints and to improve weld toughness.
• Check that the minimum design temperature is compatible with weld and HAZ toughness.

Our warehouse can supply bevelled edges and cut blanks ready for welding, which reduces work in the fabrication shop.

Corrosion resistance of 06Cr13Al is set by its chromium content: it has moderate atmospheric corrosion resistance and is immune to chloride stress-corrosion cracking. Its minimum PREN is 11.5.

For welded parts in sensitizing media, an intergranular corrosion test to GB/T 4334 can be ordered. Hydrotest water chloride content should be controlled as required by GB/T 150.4.

Media guide

The table is general guidance. Final material selection should be based on the actual medium, temperature and concentration, and where possible on plant experience or corrosion testing.

Ferritic-specific notes

Ferritic stainless steels do not suffer chloride stress-corrosion cracking in the way austenitic grades do, which is the main reason they are used in hot-water and chloride-bearing service. Their weaknesses are lower toughness, especially after welding, and sensitivity to grain growth. Stabilized ferritic grades with titanium or niobium resist intergranular corrosion after welding without heat treatment. When a design moves from austenitic to ferritic plate, check weld procedures, forming limits and minimum design temperature again rather than assuming the same rules apply.

Applications of 06Cr13Al follow from its corrosion and temperature behaviour as a pressure equipment stainless steel plate. Typical uses:

• Heat exchanger parts and liners
• Process equipment in non-chloride service
• Clad and lined vessels

Buyers specifying 06Cr13Al for these jobs often compare it with GB/T 713.7 06Cr13 S11306 and GB/T 713.7 019Cr19Mo2NbTi S11972; the comparison table on this page shows the differences.

Other GB/T 713.7 grades buyers request alongside it: GB/T 713.7 06Cr19Ni10 S30408.

Selection guidance by application

For storage tanks and low-pressure vessels the decision is usually driven by corrosion resistance and cost, and the plate thickness is moderate. For high-pressure or large-diameter vessels, strength becomes important and ferritic plate is rarely the first choice; it is used mainly for thin, low-pressure parts where SCC resistance matters. For heat exchangers the tube sheets, shells and channels often use different grades, and we can supply all of them in one order with consistent certification.

On S11348 vs 405, the alloy family is the same, but GB/T 713.7 sets its own chemistry limits and strength minimums. The table compares the grades buyers most often weigh it against, using GB/T 713.7-2023 values.

How to choose

Start from the corrosion requirement and the design temperature, then compare strength, availability and cost. A higher-alloy grade is only worth its price when the medium or temperature needs it; a lower-alloy grade that is readily available often gives a shorter lead time. Ferritic grades are chosen mainly for chloride stress-corrosion resistance and low nickel cost, within the thickness and toughness limits of the family. Our engineers can review your design conditions and suggest the most economical grade that meets the code.

Weight example: a 10 mm plate at 7.9 – 8.0 g/cm³ weighs about 79 – 80 kg/m². Ask for cut-to-size blanks to reduce scrap on heads and shells.

Tolerance and flatness notes

PT.A is the normal thickness accuracy class; PT.B gives a tighter tolerance and is useful when the designer has little corrosion allowance or when plates are rolled into shells with close fit-up requirements. Flatness depends on thickness and width, and cut-to-length plate from coil is usually flatter than as-rolled thick plate. For heads and dished ends, ask us for circular blanks cut to the developed diameter, which reduces handling and scrap at the fabricator.

We offer steel cutting services and stainless surface finishing services in our Shanghai warehouse.

Choosing a finish

No.1 is the standard finish for hot-rolled pressure vessel plate; it is suitable for shells, heads and parts that will be pickled or machined after fabrication. Cold-rolled 2B is used for thin vessels, liners and parts where a smoother surface helps cleaning. Polished finishes are specified for hygienic vessels in food and pharmaceutical plants, where surface roughness limits are part of the design. Plates can be supplied with PE film protection to prevent scratching during fabrication.

• Heat chemical analysis on every heat; product analysis by agreement
• Tensile test and hardness per Table 18
• Bend test D = 2a when ordered
• Intergranular corrosion (GB/T 4334) and UT on request
• 100% PMI and dimensional check by SHH STEEL
• EN 10204 3.1 certificate; 3.2 with SGS, BV, TUV or a named inspector

Every test result appears on the certificate with the heat number, so the plate can be traced from mill to finished vessel.

Third-party inspection

For export projects, a 3.2 certificate is often required. In that case an independent inspector witnesses sampling and testing at the mill and countersigns the certificate. We coordinate SGS, BV, TUV, Lloyd’s or a client-named inspector, and we schedule witness points so that inspection does not delay rolling. In our warehouse we check dimensions, flatness, surface condition and marking, and repeat PMI on each plate before packing.

• Standard and edition: GB/T 713.7-2023
• Grade and code: 06Cr13Al / S11348
• Thickness, width, length and quantity
• Edge EC or EM; thickness accuracy PT.A or PT.B
• Surface finish (clause 4.2)
• Extra tests: impact temperature, IGC, UT, product analysis
• Certificate type: EN 10204 3.1 or 3.2

Send the list to SHH STEEL and we return a quotation with mill, lead time and stock options.

Common ordering mistakes

• Citing GB/T 24511 instead of GB/T 713.7-2023 on new orders.
• Leaving out the surface finish, which clause 4.2 requires.
• Not stating impact test temperature when the design needs it.
• Ordering to GB/T 4237 for pressure parts; GB/T 4237 plate is not certified for pressure equipment.

A short technical review before order placement avoids these problems, and our engineering team does this free of charge.

06Cr13Al is produced by a smaller number of Chinese mills; we place mill orders through the producers we represent and confirm minimum quantities per thickness. Lead time is typically 30-40 days for mill production (production can be scheduled within 30-40 days), and we confirm the rolling slot with the quotation.

Buyers who normally purchase 405 stainless steel plate to ASTM A240 can source this grade through the same mills, with the certificate issued to GB/T 713.7-2023.

Every plate is traceable to its heat number, and copies of the mill certificates stay on file for repeat orders and audits. Mixed-grade and mixed-standard orders can be consolidated in one shipment.

Packing and export documents

Plates are packed on steel or fumigated wooden pallets with waterproof wrapping, edge protectors and steel straps, and each bundle carries labels with grade, standard, heat number, size and weight. Export documents include the commercial invoice, packing list, mill certificates, certificate of origin and, when required, inspection certificates. We ship from Shanghai port in containers or break bulk, and can consolidate mixed grades in one shipment.

GB/T 713.7 06Cr13Al (S11348) is a ferritic pressure-vessel plate grade, known internationally as 405. It is defined by Table 15 chemistry (C ≤ 0.08, Cr 11.50 – 14.50, Ni ≤ 0.60, Al 0.10 – 0.30) and Table 18 properties of Rp0.2 ≥170 MPa, Rm ≥ 415 MPa and A ≥20%. Typical uses include heat exchanger parts and liners, process equipment in non-chloride service and clad and lined vessels.

Before ordering, state the standard edition, the grade name with its code, and any extra tests, so that the mill certificate matches your design documents. SHH STEEL supplies 06Cr13Al plate from stock and by mill order, cut to size and finished in our own warehouse, with EN 10204 3.1 certificates. For related grades see GB/T 713.7 06Cr13 S11306 and GB/T 713.7 019Cr19Mo2NbTi S11972, our GB/T 713.7-2023 category and GB/T 4237 06Cr13Al S11348. Send your sizes and quantities for a quotation.