JIS G4305 SUS445J1 Steel Plate | 445J1 Stainless Steel

As a stainless steel supplier and China mill-direct exporter, SHH STEEL supplies JIS G4305 SUS445J1 Steel Plate, also known as 445J1 stainless steel. SUS445J1 is a high-chromium molybdenum ferritic grade of JIS G4305:2021, the Japanese Industrial Standard for cold-rolled stainless steel plate, sheet and strip. It contains 21.00 – 24.00 % chromium and 0.70 – 1.50 % molybdenum, with carbon limited to 0.025 % and nitrogen to 0.025 %.

JSSA describes the SUS445J1/J2 group as showing corrosion and weather resistance equal to or better than SUS444, with a pitting index (Cr + 3.3 Mo) of 25.5 – 28.5. There is no exact EN equivalent; the related grades are EN 10088-2 1.4613 plate and the Chinese GB/T 4237 019Cr23MoTi S12362 plate.

This page summarises the requirements of JIS G4305:2021 for SUS445J1: chemical composition, mechanical properties, surface finishes, standard sizes and the informative heat-treatment conditions of Annex JA. Hot-rolled plate of the same grade is ordered to JIS G 4304:2021, which also lists SUS445J1. SHH STEEL quotes either standard and confirms the edition named on the drawing before an order is placed.

Mechanical properties in JIS G4305 apply to thickness 0.30 mm and above, and the standard notes that properties after heat treatment carried out by the user are not specified. Clause 7 makes intergranular corrosion testing a matter for agreement.

JSSA describes the group as Ti,Nb-stabilised (22Cr-1~2Mo-Ti,Nb-LCN). Using Cr + 3.3 × Mo, the minimum limits give about 23.3.

These values are higher than the 175 N/mm² / 360 N/mm² of JIS G4305 SUS430LX.

JIS G4305 leaves polished finishes such as No.3, No.4, #240, #320 and #400 to the manufacturer’s method, so SHH STEEL writes the finish, the grit and any protective film into the purchase order. For ferritic sheet, No.2B, BA and HL are common; BA and HL are used for appliance and building surfaces.

Annex JA is informative. Ferritic grades are annealed rather than solution treated, and they do not harden on quenching, so either rapid or slow cooling is allowed where the annex says so.

Table 19 of JIS G4305 gives a basic mass of 7.69 kg/(mm·m²) for SUS445J1, which is used to calculate plate weight (equivalent to a density of 7.69 g/cm³). Lead time from the mill is normally 30 – 40 days after order confirmation, depending on size, finish and rolling schedule.

• Chromium 21 – 24 % with 0.70 – 1.50 % molybdenum.
• JSSA: corrosion and weather resistance equal to or better than SUS444.
• Very low carbon and nitrogen (≤ 0.025 % each).
• Proof stress ≥ 245 N/mm², tensile strength ≥ 410 N/mm².
• Magnetic in all conditions.
• Density 7.69 g/cm³ (JIS G4305 Table 19).

For pressure equipment in China, see GB/T 713.7 S12362 pressure vessel plate. Within JIS G4305, JIS G4305 SUS444 steel plate is the usual comparison.

The Japan Stainless Steel Association lists the main uses of SUS445J1/J2 as:

• Electric water heaters
• Solar panels
• Roofing and exterior building materials
• Water storage tanks

SHH STEEL confirms mill availability for this grade before quoting.

The table compares SUS445J1 with the JIS G4305:2021 grades that buyers most often consider alongside it. Chemistry is taken from Tables 3 – 7 and the minimum mechanical properties from Tables 8 – 14 of the standard, all in the condition in which the grade is normally supplied.

SUS445J1 sits between SUS444 and the super-ferritic JIS G4305 SUS447J1. It has more chromium than SUS444 but less molybdenum. SHH STEEL can quote the grades in this table side by side when a buyer is still choosing between them.

SUS445J1 is listed in both JIS G4305:2021 (cold-rolled plate, sheet and strip) and JIS G4304:2021 (hot-rolled plate, sheet and strip). The chemistry and the mechanical property tables are the same in both standards, but the product range, finish and tolerances differ:

As a rule, thin sheet and anything that needs a bright or brushed surface is ordered to JIS G4305, while heavier plate for fabrication is ordered to JIS G4304. Sizes outside the tables are possible by agreement in both standards. SHH STEEL confirms which standard and finish suit the part before quoting.

A common way to rank resistance to pitting is the pitting resistance equivalent number, PREN = %Cr + 3.3 × %Mo + 16 × %N. Calculated from the JIS G4305 limits, SUS445J1 has a PREN of about 23.3 at the minimum of every range and about 29.3 at the maximum. PREN is a ranking tool, not a guarantee of performance in a given environment, and actual heats normally sit between these values; the certificate analysis gives the real figure for each heat. SHH STEEL can calculate the PREN of the heat offered from its certificate before the order is confirmed.

JSSA rates the SUS445J1/J2 group equal to or better than SUS444 for corrosion and weather resistance, with a pitting index (Cr + 3.3 Mo) of 25.5 – 28.5. Very low carbon and nitrogen (0.025 % maximum each) limit chromium carbide and nitride formation. Like other ferritic grades, it is generally less prone to chloride stress corrosion cracking than the 300-series austenitic grades, which suits water heaters and storage tanks.

Where resistance to intergranular corrosion must be demonstrated, clause 7 of JIS G4305 lets the purchaser specify one of four test methods: JIS G 0571 (oxalic acid etch test), JIS G 0572 (ferric sulphate – sulphuric acid test), JIS G 0573 (65 % nitric acid test) or JIS G 0575 (copper sulphate – sulphuric acid test). One test piece is taken per heat and heat-treatment lot. SHH STEEL writes the chosen method and acceptance criterion into the mill order when a project requires it.

SUS445J1 is a ferritic steel. Ferritic grades are welded with lower heat input than austenitic grades, because grain growth in the heat-affected zone can reduce toughness and ductility; stabilised and low-interstitial grades are designed to limit this effect. Thin sheet is commonly joined by TIG, plasma, resistance or laser welding. Ferritic steels have lower thermal expansion than austenitic steels, so they distort less during welding and in thermal cycling.

In forming, ferritic sheet has lower work hardening than austenitic sheet and is often chosen for deep-drawn appliance parts; its bend requirement in JIS G4305 Table 11 is checked by the mill. Annealing per Annex JA is 850 – 1 050 °C with rapid cooling, so any re-annealing after severe forming should follow that range.

SHH STEEL can deliver SUS445J1 cut to size, bevelled or pre-formed through its processing partners, so that the fabricator receives parts ready for welding.

• Use low heat input and avoid unnecessary multi-pass welding.
• Use filler metal approved for high-chromium ferritic steel.
• Clean and passivate after fabrication for exterior use.
• For roofing and cladding, agree the surface finish and protective film before forming so that the visible face is not damaged.

JIS G4305:2021 clause 9 sets the tolerances for cold-rolled plate, sheet and strip, and SHH STEEL checks thickness at the positions the standard defines before shipment. Thickness tolerances for plate are given in Table 20 and depend on thickness and width:

Tighter thickness tolerances can be ordered with the symbols ET (Table 22) or ST (Table 23), and narrower width tolerances with EW (Table 26). Plate width tolerance (Table 24) is +10 / 0 mm for lengths up to 3 500 mm, and plate length tolerance (Table 27) is +10 / 0 mm for thickness under 10 mm and lengths up to 3 500 mm. Flatness is measured on request: Table 28 allows 15 – 20 mm per 3 500 mm length, or 3 – 6 mm when the special flatness symbol EF is ordered.

For hot-rolled SUS445J1 plate ordered to JIS G 4304, the tolerances of that standard apply. SHH STEEL states the tolerance symbols on the quotation so that the buyer knows exactly which table the plate will be measured against.

Clause 11 of JIS G4305 sets the test rules. Chemical analysis follows JIS G 0404 and JIS G 0320, and a product (check) analysis to JIS G 0321 can be requested by the purchaser. For mechanical tests, one sample is taken from plate or strip of the same heat and the same heat-treatment condition, and one test piece is used for each test.

• Tensile test to JIS Z 2241 at 23 ± 5 °C, using test piece No. 4, No. 10 or No. 13B (No. 14A, 14B or 5 also allowed).
• Hardness test to JIS Z 2243-1 (Brinell), JIS Z 2244-1 (Vickers) or JIS Z 2245 (Rockwell), at 23 ± 5 °C.
• Bend test to JIS Z 2248 where the grade has a bend requirement; the manufacturer may omit it, but the material must still meet it, and it must be done if the purchaser asks.
• Inspection of chemistry, mechanical properties, surface finish, dimensions and appearance under clause 12; corrosion resistance only when specified.

Under clause 13 each plate or bundle is marked with the grade symbol, dimensions, any special tolerance or flatness symbols (ET, ST, EW, EF), the surface finish, the heat-treatment symbol where applicable, the manufacturer’s name or mark, and the heat or inspection number. Clause 14 makes the inspection document JIS G 0415 type 3.1 unless another type is ordered; SHH STEEL checks the marking against the certificate before shipment, and a third-party inspector arranged by SHH STEEL can witness the tests when a 3.2 document is required.

A complete enquiry avoids delays and wrong deliveries. For SUS445J1 we recommend stating:

• Standard and edition: JIS G 4305:2021 (cold rolled) or JIS G 4304:2021 (hot rolled), grade SUS445J1.
• Product form: plate, sheet, coil or strip; thickness, width and length, or coil inner diameter and weight.
• Tolerance and flatness symbols if tighter than standard (ET, ST, EW, EF).
• Surface finish from Table 15 (No.2D, No.2B, BA, HL) or a polished finish with grit and protective film.
• Heat-treatment condition, and any intergranular corrosion test method (JIS G 0571 – 0575).
• Inspection document type (JIS G 0415 3.1 by default, 3.2 if third-party witness is needed).
• Any dual certification required, for example to ASTM A240 or EN 10088-2, and any product analysis or PMI.
• Packing, marking and destination port; SHH STEEL can add customer marking or bar codes on request.

SHH STEEL reviews every enquiry against these points and confirms in writing anything that the mill cannot meet before the order is placed.

Table 18 of JIS G4305 calculates plate mass from the basic mass in Table 19, which for SUS445J1 is 7.69 kg per mm of thickness per m² of area. The basic mass is multiplied by the thickness in millimetres to give the unit mass in kg/m², then by the plate area in m², and the result is rounded as the table specifies.

Invoiced weight may be calculated (theoretical) or actual (weighed), and this should be agreed at the order. SHH STEEL states which method is used on the quotation, and the SHH STEEL packing list shows both the calculated and the actual weight of each bundle.

As a SUS445J1 supplier, we find that buyers usually worry less about price than about getting the right material on time. The table below lists the concerns we hear most often and how SHH STEEL deals with each one.

SHH STEEL also offers steel cutting services, bending and forming services, a third-party testing service with partner laboratories, and a worldwide shipping service. See our full range of stainless steel sheets and plates.

JIS G4305 SUS445J1 Steel Plate (445J1 stainless steel) is a 22 % chromium, molybdenum-bearing ferritic grade used for water heaters, solar panels and exterior building materials. SHH STEEL supplies it with full JIS G4305 compliance, 3.1 inspection certificates and optional third-party testing, with a normal lead time of 30 – 40 days. Contact SHH STEEL for availability, sizes and a quotation for your SUS445J1 requirement.