NS-Siam United Steel Co.

What NS-Siam United Steel Co. does

NS-Siam United Steel Co., Ltd. (NS-SUS) is a privately held Thai flat-steel manufacturer headquartered in Rayong, Thailand, producing seven core product lines spanning the value chain from cold rolled steel (CRS) and galvanized iron substrate (GIS) to hot-dip galvanized (GI), galvannealed (GA), tin mill black plate (TMBP), electrolytic tinplate (TP), and tin-free steel (TFS). The company operates three integrated manufacturing plants in Rayong's Maptaphut industrial estates covering cold rolling, hot-dip galvanizing, and electrolytic plating, leveraging proprietary Nippon Steel technology including a 6-high 5-stand rolling mill for precision thickness control and patented surface treatment processes. NS-SUS holds IATF 16949, ISO 9001, ISO 14001, and ISO 45001 certifications and achieved JIPM World-class TPM status in 2020.

NS-SUS serves enterprise B2B customers across four primary verticals — automotive, electrical appliances, construction and infrastructure, and food/beverage packaging — with a stated base of 2000+ customers, supplying cold rolled, galvanized, galvannealed, and tin-coated steel for body panels, appliances, roofing, and food cans respectively. The company is a strategic member of the Nippon Steel group: Nippon Steel Corporation is a major shareholder and technology partner, Nippon Steel Trading Corporation handles distribution, and the entity was formed through the 2016 merger of Siam United Steel (1995) and Nippon Steel & Sumikin Galvanizing (Thailand), followed by a 2022 merger with Siam Steel Vilas. Ownership is private with no public listing; revenue is not publicly disclosed.

The business model is direct B2B sales through a dedicated sales office in Bangkok and a Rayong-based direct sales team, with quote-based pricing on multi-year enterprise contracts. Go-to-market combines direct account management with onsite technical services (steel seminars, plant tours, materials development and testing) and digital channels (Mill Sheet Online, Chemical Certificate, IC Verification System, social media on Facebook, LINE, YouTube, TikTok). Operational excellence is a core differentiator — seven consecutive years of zero lost-time accidents, machine downtime reduced to 0.28%, prime yield at 95.4%, and OEE above 90% — built on 30+ years of TPM culture under JIPM methodology.

Name

NS-Siam United Steel Co.

Legal name

บริษัท เอ็นเอส-สยามยูไนเต็ดสตีล จำกัด (NS-SIAM UNITED STEEL CO., LTD.)

Website

https://ns-sus.com

Company type

Private

Founded year

1988

Operating status

Operating

Headcount range

1,001–5,000 employees

Short description

NS-Siam United Steel (NS-SUS) is a privately held Thai manufacturer of cold-rolled, galvanized, and electrolytic-coated flat steel products, operating three integrated plants in Rayong under Nippon Steel technology partnerships, supplying automotive, appliance, construction, and packaging OEMs across Thailand and ASEAN.

Ownership category

akta.pro rank

Product category

Flat Steel Products

NAICS

Rolling and Drawing of Purchased Steel (33122), Metal Coating, Engraving (except Jewelry and Silverware), and Allied Services to Manufacturers (332812)

SIC

Steel Works, Blast Furnaces & Rolling & Finishing Mills (3310)

akta.pro primary industry

Coated & Plated Steel (Galvanized, Galvalume, Tinplate, Electrogalvanized, Color-Coated) (IMAKABAG)

akta.pro secondary industry

Steel Service Centers & Processing (Slitting, Cut-to-Length, Blanking, Leveling) (IMAKABAL)

Keywords

• Cold rolled steel
• Galvanized steel
• Tinplate manufacturing
• Coated steel sheets
• Flat steel products

Headquarters

HQ city

Rayong

HQ country

Thailand

HQ region

Asia

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Supply Chain, Personnel, Operations, Infrastructure, Technology or R&D, Marketing or Sales

Revenue model

1. Steel Products Sales: Direct sales of cold rolled steel, galvanized steel, galvannealed steel, tinplate, and tin-free steel products to manufacturers in automotive, electrical appliances, construction, and packaging industries. Revenue generated through product sales with quotes provided based on specifications and volumes.

Pricing tiers

Go-to-market motion1 record

Distribution channels1 record

Marketing channels6 records

Core offering

NS-SUS manufactures and supplies a portfolio of flat steel products — Cold Rolled Steel (CRS), Galvanized Iron Substrate (GIS), Galvanized Iron (GI), Galvannealed (GA), Tin Mill Black Plate (TMBP), Tin Plate (TP), and Tin-Free Steel (TFS) — to industrial manufacturers across automotive, electrical appliances, construction, and packaging sectors. Production is integrated across three Rayong-based plants covering cold rolling, hot-dip galvanizing, and electrolytic plating, with sales handled directly through the Bangkok sales office.

Product overview

NS-Siam United Steel (NS-SUS) is a steel manufacturer producing a portfolio of 7 main steel products spanning the value chain from raw materials to finished coated steels. The core product is CRS (Cold Rolled Steel), which serves as the starting material for most downstream products. TMBP (Tin Mill Black Plate) is the raw substrate for the plating lines producing TP (Tin Plate) and TFS (Tin-Free Steel). GIS (Galvanized Iron Substrate) feeds the GI (Galvanized Iron) hot-dip line, while GA (Galvannealed) undergoes additional annealing for enhanced paintability. Products serve diverse industries including automotive, construction, electrical appliances, furniture, and food/beverage packaging.

Differentiator

Problem solved

Functional benefit

Products and services

• CRS (Cold Rolled Steel / เหล็กแผ่นรีดเย็น) Cold-rolled steel sheet produced at NS-SUS, used as raw material for downstream industries including automotive, electrical appliances, furniture, and containers. Features superior formability, dent resistance, excellent surface quality, and lightweight properties.
• TP (Tin Plate / เหล็กแผ่นเคลือบดีบุก) Electrolytic tin-plated steel sheet coated with tin on both sides, offering excellent corrosion resistance, safety for food contact, and bright surface finish. Used for food and beverage cans, spray cans, and lid applications.
• GA (Galvannealed / เหล็กกัลวานิล) Hot-dip galvanized steel that undergoes annealing to create an alloy layer, providing superior corrosion resistance, excellent paint adhesion, and good weldability. Primarily used in automotive body panels, electrical appliances, and furniture.
• GIS (Galvanized Iron Substrate / เหล็กรีดเย็นสำหรับชุบสังกะสี) Cold-rolled steel substrate specifically designed for subsequent zinc galvanizing. Features excellent flatness and ability to produce ultra-thin steel, particularly important for construction applications especially roofing.
• GI (Galvanized Iron / เหล็กกัลวาไนซ์) Hot-dip galvanized steel providing rust and corrosion protection. Available in Minimize Spangle and Zero Spangle variants. Used in automotive, electrical appliances, and construction industries with long-term durability.
• TMBP (Tin Mill Black Plate / เหล็กแผ่นรีดเย็นสำหรับชุบดีบุก) Raw material for producing Tin Plate (TP) and Tin-Free Steel (TFS). Features excellent coating adhesion, high strength for impact and bend resistance. Used in food and beverage cans, oil/gas drums, and paint containers.
• TFS (Tin-Free Steel / เหล็กปลอดดีบุก) Electrolytic Chromium Coated Steel (ECCS) coated with chromium and chromium oxide layers. Features excellent lacquer adhesion, corrosion resistance, and abrasion resistance. Used for food cans, spray cans, lids, and industrial packaging.

Named customers4 records

Segments4 records

Ideal customer profiles4 records

Technology focussed Yes

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Three partnerships are on record, tiered core.

• Thai Tinplate Manufacturing Co., Ltd. (TTP)coreStrategic or Co-development Partner · 1 June 2011Thai Tinplate Manufacturing (Siam Tinplate) merged with the company in 2011, forming the current NS-SUS entity and adding tinplate production capabilities to the product portfolio.
• Nippon Steel Trading Corporation (NST)coreStrategic or Co-development Partner · 1 July 1995Nippon Steel Trading Corporation serves as a strategic shareholder and trading partner, facilitating international market access and distribution of NS-SUS steel products alongside Nippon Steel's global network.
• Nippon Steel Corporation (NSC)coreStrategic or Co-development Partner · 1 August 1988Nippon Steel Corporation, Japan's largest steel manufacturer, is a major shareholder and technology partner of NS-SUS. NSC provides advanced steel manufacturing technology, process expertise, and technical knowledge transfer including proprietary surface treatment technologies and production methodologies.

Scale indicators8 records

Recent moves11 records

Expansion highlights5 records

Broad incumbents

• JFE Steel Corporation: Japanese integrated steelmaker producing cold rolled, galvanized, and electrical steel for automotive and industrial applications. Similar product mix to NS-SUS in coated flat steel, with larger global production footprint.
• Nippon Steel Corporation: Japan's largest steel producer and NS-SUS's major shareholder/technology partner. Produces the full flat steel spectrum including CR, GI, GA, and tinplate; provides the proprietary technologies (6-high rolling, GA coatings) used by NS-SUS. Comparable product portfolio, much larger integrated scale.
• Hyundai Steel: Korean integrated steelmaker producing cold rolled, galvanized, and coated steel for automotive (including Hyundai Motor Group) and construction. Comparable product portfolio with large-scale integrated mill economics.
• POSCO: South Korea's largest steelmaker producing cold rolled, galvanized (GI/GA), and tinplate products serving global automotive, appliance, and packaging markets. Directly comparable product portfolio, though at significantly larger scale and broader geographic footprint.
• ArcelorMittal: World's largest steelmaker with extensive flat product operations including galvanized, galvannealed, and electrical steel across multiple continents. Overlaps with NS-SUS on automotive and appliance customer base but at vastly larger scale and integrated upstream.

Direct peers

• Marcegaglia: Italian independent steel processor specializing in cold rolled, galvanized, and tinplate products for construction, packaging, and appliances across Europe and international markets. Closely comparable as a non-integrated steel processor focused on coated flat products.
• BlueScope Steel: Australian steelmaker specializing in metallic-coated and painted steel products (Zincalume, Galvabond) for construction and appliance markets. Closely comparable in coated flat steel product focus and downstream customer base.
• Tata Steel: Indian-headquartered global steelmaker with cold rolling, galvanizing, and tinplate operations across Asia and Europe. Operates comparable downstream coated steel lines serving automotive and packaging end markets, including Thailand/ASEAN exposure.

Regional players

• G Steel Public Company Limited: Thai hot-rolled and cold-rolled steel producer serving domestic automotive, construction, and appliance markets. Headquartered in Thailand with overlapping customer base and product range to NS-SUS.
• Sahaviriya Steel Industries (SSI): Thailand's largest hot-rolled steel producer (now under Delong/Chinese ownership), with downstream cold rolling and galvanizing capacity. Direct regional competitor in Thai flat steel market serving overlapping automotive and construction customers.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks1 record

Key highlights7 records

Customer concentration

• YouTubeyoutube.com/channel/UCEf8OryLn2XapWSwL9-HNmQ
• Facebookfacebook.com/profile.php
• TikToktiktok.com/@nssiamunitedsteel

Compliance4 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles2 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about NS-Siam United Steel Co.