Pakistani Customer Visits for 1045 / 4140 / 4130 Steel Plate and Round Bar

Release Tme: 2026-10-16

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1045, 4140 and 4130 are three engineering steels that usually travel together in one order. 1045 is a plain medium-carbon steel for shafts, gears and machine parts. 4130 and 4140 are chromium-molybdenum alloy steels: 4130 is chosen when a part must be welded after heat treatment, 4140 when it must carry load. Sourcing all three from one mill gives the whole consignment one chemistry standard, one certificate format and one inspection record.

A procurement and quality team from Pakistan visited GNEE STEEL to review steel plate and round bar in these three grades. The review ran over two days. It covered the rolling source, the stock we hold, and the test reports that travel with every heat. It closed with a confirmed order for plate and round bar in 1045, 4140 and 4130. The team went home with mill test certificates, sample pieces and a signed-off specification list.

Why These Three Grades Travel Together

Grade	C	Mn	Si	Cr	Mo	UNS
1045	0.43–0.50	0.60–0.90	0.15–0.35	—	—	G10450
4130	0.28–0.33	0.40–0.60	0.15–0.35	0.80–1.10	0.15–0.25	G41300
4140	0.38–0.43	0.75–1.00	0.15–0.35	0.80–1.10	0.15–0.25	G41400

Composition per SAE J403 / J404, cast analysis, weight %.

Carbon is where the three separate. 1045 holds enough carbon to respond to flame or induction hardening, reaching 54–60 HRC at the surface while the core stays near 180 HB. 4130 sits lower in carbon, which is why it welds. 4140 carries the carbon of 1045 plus chromium and molybdenum, so it hardens deeper and holds its strength in larger sections.

The Mechanical Numbers Buyers Misread

Grade	Condition	Tensile Rm (MPa)	Yield Rp0.2 (MPa)	Hardness
1045	Hot rolled	570–700	310–450	170–210 HB
1045	Q&T	≈760	≈530	≈220 HB
4130	Q&T	850–1000	650–750	22–28 HRC
4140	Q&T	1000–1200	850–1000	28–32 HRC

Indicative values for a 25 mm ruling section, quenched and tempered at a mid-range tempering temperature. The mill test certificate governs.

These numbers do not scale with size. Hardenability is the limit. 1045 responds reliably to water quenching to roughly 20–25 mm, 4130 to about 50 mm in oil, and 4140 to close to 100 mm in oil. Order a 150 mm 4140 bar and its core will be softer than its surface. That is not a defect. It is the grade behaving as it should. Give us the section size before we quote.

Welding follows the same logic. 4140 has a carbon equivalent of about 0.75–0.85 and needs 300–400 °C preheat, low-hydrogen consumables and post-weld stress relief. 4130 sits near 0.55–0.65 and is far more forgiving. 1045 is not a welding grade. It is machined, then heat treated.

Equivalent Grades Across Standards

AISI / SAE	EN	JIS	GB/T
1045	C45 (1.0503), EN 10083-2	S45C, JIS G4051	45, GB/T 699
4130	25CrMo4 (1.7218)	SCM430, JIS G4105	30CrMo, GB/T 3077
4140	42CrMo4 (1.7225)	SCM440, JIS G4053	42CrMo, GB/T 3077

Always name the standard, not just the grade number. A 4140 order placed to EN 10083-3 and one placed to ASTM A29 do not carry the same guaranteed properties or the same certificate.

Where Orders Like This Usually Go Wrong

Properties quoted for a 25 mm bar are applied to a 150 mm one, and the part fails in service.
Plate and bar come from two different mills, so the buyer receives two certificate formats and two hardness scales.
The delivery condition is missing from the contract. "4140" on its own says nothing about annealed or quenched and tempered.
Black bar is shipped unprotected on a long sea leg and arrives with surface rust the machine shop has to remove.

How We Ship Plate and Bar

Short pieces move in 20-foot containers. Long bars and heavy plate go breakbulk, because forcing them into a container raises the handling count and the damage risk. We strap in bundles, separate layers with timber dunnage, and wrap machined surfaces in VCI paper. The load is spread evenly and lashed in the container or on the vessel. Documents travel with the cargo: commercial invoice, packing list, mill test certificate to EN 10204, certificate of origin and bill of lading.

Frequently Asked Questions

1. What is the minimum order quantity?
Trial quantities are accepted, and mixed sizes can share one container. You can test a new grade without filling a container.

2. Do you supply cut-to-length plate?
Yes. We cut to your drawing and can rough-machine it, so your shop receives parts ready for the first operation.

3. What delivery conditions are available?
Hot rolled, normalized, annealed and quenched and tempered. Bar surfaces are available black, turned, peeled or ground.

4. How long does delivery take?
Stock sizes ship in days. Non-stock sizes follow the mill rolling schedule, which we give you before you confirm.

Send us your grade, standard, section sizes, tonnage and destination port. We confirm availability, supply condition and certificate type within one working day. Samples are available for your own machining and heat-treatment trials.

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