Sejin Heavy Industries

What Sejin Heavy Industries does

Sejin Heavy Industries (KOSPI: 075580) is a South Korea-headquartered manufacturer of ultra-large shipbuilding equipment and offshore structures, founded in September 1999 and based in Ulsan. The company produces specialized marine components — Deck Houses, Upper Deck Units, LPG/LNG/LEG cryogenic Tanks, Living Quarters, Topside Modules, Plant Modules, and floating offshore wind structures — that are integrated into vessels and offshore platforms built by major Korean and international shipyards. Its core technology base combines large-scale steel fabrication, advanced welding (certified across seven classification societies including ABS, DNV GL, LR, KR, NK, BV), cryogenic tank engineering for liquefied gases, and proprietary spray insulation systems, supported by 718,647㎡ of production infrastructure including an 80m x 60m Goliath crane with 450-ton lifting capacity.

The company operates a B2B project-based revenue model, supplying turnkey custom-manufactured components through direct sales teams to anchor customers HD Hyundai Heavy Industries, Hyundai Mipo Shipyard, DSME, and STX Shipbuilding. Sejin holds exclusive supplier positions in multiple categories — 100% of Hyundai Mipo's Upper Deck Unit needs, exclusive Deck House supply to HHI and Hyundai Mipo, and 100% domestic Korean market share in LPG Tank production — with revenue recognized on a one-time project basis at delivery. Its customer base has diversified into energy and EPC modules (Samsung Engineering's PEMEX refinery, GS Caltex olefin facility) and international shipyards (Brazil E.A.S., India Pipavav, US Vigor), while a wholly-owned Sejin Vietnam subsidiary established in 2012 serves Hyundai Vinashin and regional Southeast Asian shipbuilders.

The business is expanding into renewable energy through offshore wind partnerships (Ulsan City/Vestas, KNOC, Goldyang Green Power OSS consortium) and launched a new LCO2 tank product line in 2024 following its ASME Boiler and Pressure Vessel license acquisition. Recent corporate moves include a new ship parts factory groundbreaking in Vietnam (July 2026, up to 57 billion KRW investment) targeting 3x production capacity, and a leadership transition appointing Kim Jin-jong as Representative Director in March 2026.

Name

Sejin Heavy Industries

Legal name

(주)세진중공업

Website

https://sejinheavy.com

Company type

Public

Founded year

1999

Operating status

Operating

Headcount range

251–500 employees

Short description

Sejin Heavy Industries is a South Korean manufacturer of ultra-large shipbuilding equipment — including Deck Houses, LPG/LNG cryogenic tanks, Upper Deck Units, and offshore wind structures — that serves as an exclusive supplier to major Korean shipbuilders like HD Hyundai Heavy Industries and Hyundai Mipo.

Ownership category

akta.pro rank

Product category

Shipbuilding Equipment Manufacturing

NAICS

Ship and Boat Building (3366), Ship Building and Repairing (336611), Metal Tank (Heavy Gauge) Manufacturing (33242)

SIC

Ship & Boat Building & Repairing (3730), Fabricated Plate Work (Boiler Shops) (3443)

akta.pro primary industry

Outfitting Modules & Skids (Accommodation, Machinery, E-House, Pipe Racks) (IMAJAKAF)

akta.pro secondary industries

LPG & Ammonia Carrier Shipbuilding (IMAJAAAE), Offshore Wind & Renewable Support Vessel Construction (SOV, CTV, WTIV) (IMAJACAG)

Keywords

• Shipbuilding equipment
• Marine components
• Cryogenic tanks
• Offshore modules
• Ship block fabrication

Headquarters

HQ city

Ulsan

HQ country

South Korea

HQ region

Asia

Offices3 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

Personnel, Supply Chain, Infrastructure, Operations, Others

Revenue model

1. Ship Block Manufacturing: Manufacturing and supply of ultra-large ship components including Deck House, Upper Deck Unit, Living Quarter, and Topside Module. Revenue recognized upon delivery with project-based pricing.
2. LPG/LNG Tank Production: Production of cryogenic tanks for LPG carriers, LNG carriers, and gas carriers. Key growth driver with increasing demand for LNG-powered vessels due to IMO environmental regulations.
3. Plant Module Manufacturing: Module construction for onshore plants (oil refinery, petrochemical facilities). Projects include Samsung Engineering PEMEX refinery and GS Caltex olefin production facility expansions.
4. Offshore Wind Business: Production of floating offshore wind turbine structures (Floaters) and offshore substation (OSS) topside modules. Emerging business segment targeting renewable energy sector.

Pricing tiers

Go-to-market motion2 records

Distribution channels3 records

Marketing channels4 records

Core offering

Sejin Heavy Industries manufactures ultra-large custom shipbuilding equipment components including Deck House (crew accommodation modules), Upper Deck Unit (tanker upper deck assemblies), cryogenic LPG/LNG/LEG/ammonia tanks for gas carriers, Living Quarter structures for offshore platforms, Topside Modules for offshore oil/gas extraction, and land-based Plant Modules (PAR/PAU/PAB). The company supplies these to major Korean and international shipbuilders with turnkey capability covering design, fabrication, installation, and commissioning.

Product overview

Sejin Heavy Industries is a Global No.1 ultra-large shipbuilding equipment manufacturer producing specialized marine and offshore components. The company operates a single unified product portfolio centered around ultra-large shipbuilding equipment, with seven main product categories: Deck House (ship crew accommodation - market leader), Upper Deck Unit (ship hull upper deck), LPG/LNG Tank (liquefied gas storage), Living Quarter (offshore accommodation), Topside Module (offshore processing equipment), Plant Module (land-based industrial modules), and Wind Business (offshore wind power equipment). These products share core competencies in large-scale steel fabrication, welding, insulation, and module assembly, with the company leveraging its 718,647㎡ production infrastructure to serve major Korean shipbuilders including Hyundai Heavy Industries and Hyundai Mipo.

Differentiator

Problem solved

Functional benefit

Products and services

• Deck House Accommodation module for ship crew providing living spaces, navigation and communication facilities. Composed of 4-9 floors including bridge, captain's quarters, officer cabins, mess hall, and recreational facilities. For shipbuilders constructing commercial vessels.
• Upper Deck Unit Upper deck component installed on the top level of ship hulls from bow to stern, containing piping, electrical cables, walkways, and steel fittings. Specialized for Tanker vessels including Crude Oil Tanker, Product Carrier, Chemical Tanker, and LPG vessels. For shipbuilders.
• LPG/LNG Tank Liquefied gas storage containers for LPG, LNG, ethylene, and ammonia carriers requiring high-pressure and ultra-low temperature capabilities. Products include LPG Cargo Tank, LEG Tank, and LNG Tank. For gas carrier shipbuilders.
• Living Quarter Multi-story offshore accommodation structure (4-6 floors) for offshore oil/gas extraction facilities, featuring helicopter pad, water treatment, generators, heating, ventilation, air conditioning, and facilities for over 200 crew members. For offshore platform builders and operators.
• Topside Module Offshore oil/gas extraction equipment modules including Accommodation Barge and e-House products. Includes small Hull Block and Topside Module production for offshore processing. For offshore oil & gas developers.
• Plant Module Land-based plant modules including PAR (Pre-assembled Rack), PAU (Pre-assembled Utility), and PAB (Pre-assembled Building). For oil refineries, petrochemical plants, and energy facilities.
• Wind Business Floating offshore wind power equipment including substructures (Floaters) and onshore/offshore substations (OSS). The OSS contains high-value electronic equipment and office modules in modular form. For offshore wind farm developers and operators.

Quantifiable outcome

• 100% domestic market share in LPG Tank production
• +3 more outcomes

Named customers10 records

Segments3 records

Ideal customer profiles3 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature5 records

Partnerships

Seven partnerships are on record, tiered core and minor.

• Goldyang Green PowercoreStrategic or Co-development Partner · 1 August 2022Consortium partner for offshore wind turbine OSS (Offshore Substation) production and supply. Sejin participates as module/block manufacturer in the consortium.
• Ulsan City / VestascoreStrategic or Co-development Partner · 1 March 2022Business agreement for floating offshore wind power generation projects, signed with Ulsan City and Vestas to participate in Korea's offshore wind energy sector.
• Hyundai Heavy IndustriescoreStrategic or Co-development Partner · 1 March 2022Mutual growth agreement for smart production technology application, focusing on digital transformation and advanced manufacturing processes in shipbuilding.
• Korea National Oil Corporation (KNOC)coreStrategic or Co-development Partner · 1 July 2020Business agreement for floating offshore wind power generation projects, collaborating on renewable energy initiatives.
• Brazil E.A.S. ShipyardminorStrategic or Co-development PartnerInternational partnership for Deck House supply. First delivery in August 2018, representing Sejin Heavy Industries' entry into South American shipbuilding market.
• India Pipavav ShipyardminorStrategic or Co-development PartnerPartnership for Deck House supply to Indian shipyard for PSV and AHTS vessels. Multiple deliveries including August 2012.
• Sejin VietnamcoreOthersFirst overseas subsidiary established November 2012. Located within Hyundai Vinashin yard in Ninh Hoa District, Khanh Hoa Province, Vietnam. Uses 25,000m² facility with annual production capacity of approximately 6,000 tons.

Scale indicators14 records

Recent moves10 records

Expansion highlights6 records

Direct peers

• Chart Industries: US-based cryogenic equipment manufacturer with leading positions in LNG, LPG, and ammonia storage tanks for shipping and industrial applications. Directly comparable to Sejin's LPG/LNG/LEG/Ammonia tank business.
• TGE Marine Gas Engineering: Germany-headquartered specialist in cargo handling and gas carrier systems (LPG, LNG, LEG, ammonia). Competes with Sejin in the cryogenic tank and gas carrier equipment market.
• Sembcorp Marine: Singapore-based offshore and marine engineering group building offshore platforms, modules, and ship repair. Directly comparable to Sejin's offshore Topside Module and Living Quarter business.

Broad incumbents

• Alfa Laval: Swedish marine and process equipment supplier with strong presence in heat transfer, separation, and fluid handling for shipbuilding. A broad incumbent serving overlapping shipyards but with a different product focus than Sejin.
• Wärtsilä: Finnish marine systems incumbent offering ship power, gas solutions, and LNG fuel systems. Overlaps with Sejin's LNG fuel tank and FGSS offerings but across a much broader marine portfolio.
• Konecranes: Global lifting equipment manufacturer (overhead cranes, hoists). Indirectly comparable via Sejin's reliance on heavy-lifting infrastructure (Goliath crane) and the broader heavy-fabrication ecosystem.

Regional players

• Vigor Industrial: US Pacific Northwest shipyard and marine fabrication company supplying Navy, ferries, and commercial vessels. Comparable regional player in marine outfitting and module manufacturing.

Others

• HD Hyundai Heavy Industries: Korea's largest shipbuilder and Sejin's primary customer. Not a direct competitor (Sejin is a Tier-1 supplier) but the relationship is material; HHI also builds ship blocks and modules in-house.

Emerging players

• Bladt Industries: Danish fabricator of offshore wind foundations, substations, and transition pieces. Comparable to Sejin's Wind Business (Floaters, OSS) and offshore module fabrication.
• Sif Group: Netherlands-based manufacturer of monopile foundations for offshore wind. Comparable emerging play in the offshore wind substructure supply chain Sejin is targeting in Korea.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks7 records

Key highlights7 records

Customer concentration

• LinkedInlinkedin.com/company/sejin-innotech-co-ltd-

Compliance6 records

Revenue estimate

Valuation estimate

Number of profiles

Subsidiaries1 record

Funding overview

Funding rounds

Investors

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

M&A

Investments1 record

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

Frequently asked questions about Sejin Heavy Industries