Message from the President

Our company has, since its founding, focused its attention on the potential of stainless steel, and has manufactured a variety of welded products using stainless materials.

Now, the societal environment around us is changing at a bewildering pace, and the social responsibility and functionality required of our products is growing and becoming more complex every day. Our company has established welding technique as its core competency, and consistently striven to better our welding process. It is my hope that, through application and use of our many years of experience and the latest materials and manufacturing techniques, we can provide not simply welded goods but goods with a real, new added value.
I desire for our company to be the kind of company that turns today's problems into tomorrow's possibilities, the kind of company whose growth and improvement is truly visible to all around.

In the society in which we live, no one can live on their own. We are all affected by many people, and even unintentionally influence those around us. Our company will strive to treasure its bonds with all of you, make every effort to continue creating products that serve the good of society, and work to share the joy we have received.

I hope we can look forward to your continued support and encouragement in the years to come.

Katsuhiko Hara, President of Seiwa Industrial Corporation

Company Outline

Name Seiwa Industrial Corporation
Business established April, 1962
Company founded December 15, 1965
Head office 3-105 Kitahonmachi, Itami, Hyogo 664-0836 Japan
and Main Plant Phone:+81-72-782-0281
Nara plant Showa Industrial Park, 1 Shigicho,
Yamatokoriyama, Nara 639-1039 Japan
Fukuchiyama plant 2758, Aza Osada Oono Shimo, Fukuchiyama, Kyoto 620-0851 Japan
Capitalization 24,000,000yen
Corporate officers Chairman       Seiichi Yamashita
President      Katsuhiko Hara
Executive director  Kazuo Kashiwamura
Auditor       Yukari Yamashita
Annual Sales 4.2 billion yen(2017)
Number of employees 250
Bank references Senshu Ikeda Bank, Mukonoso Branch
Mitsui Sumitomo Bank, Itami Branch
Risona Bank, Kawanishi Branch
Primary businesses Manufacture of residential equipment
 (Electric water heaters, water heaters, commercial
 hot water tanks, etc.)
Manufacture of industrial environment equipment
 (Environment testers and testing equipment for research
 facilities, medical stainless steel products, boiler tanks,
Manufacture of equipment for space travel
 (Battery cases, etc.)

Corporate History

1962 Stainless steel processing and commercial kitchen equipment Manufacturing business is established.
1965 Company is incorporated.
1968 Manufacturing of tanks for small stainless steel electric water heaters begins.
Company enters the electric appliance market
1971 Production of mid-size enamel-lined tanks for electric water
heaters begins(with development of inner-surface welding technology.)
1974 Japanese Defense Agency awards the company MIL certification for stainless steel spot welding. Nara Plant is opened.
1977 Company is registered as a manufacturer of electric heating appliances.
1978 Assembly of small water heaters begins.
1983 Sterilizing hand washer is marketed.
1985 Company is granted a practical-use patent for its sterilizing hand washer.
Small stainless steel electric water heater is developed.
Production of mid-size cylindrical stainless steel electric water heater begins.
Inner-surface welding technique is refined.
1990 Company is granted a patent for its high-grade ferrite stainless steel cylinder manufacturing technique.
1996 Main Office plant No.2 begins operation.
2000 Main plant is awarded certification of registration with ISO14001.
Production of a high-pressure electric water heater begins.
2004 Main Office and Nara plant is awarded certification of registration with ISO9001
2005 Production of parts for fuel cells begins.
Nara Plant is awarded certification of registration with ISO 14001.
2006 Main Office plant No.2 expanded
2007 Fukuchiyama plant starts construction
Patent received for structural welding of cylinders
2008 High-volume production of steam reformers for fuel cells begins
Production of water heaters for aircraft begins
2009 Assembly of household heat pump-type water heaters begins
2011 Assembly of industrial heat pump-type water heaters begins
2013 Hot beer server commercialization.
2014 Production of fuel cell power generation module housings begins
2015 Fukuchiyama plant is awarded certification of registration with ISO 14001,ISO 9001
2016 High-volume production of HYDOROTYZER begins

Major Customers

Panasonic Corporation
LIXIL Corporation
Nihon Itomic Co.,LTD.
Takara Standard Co.,Ltd.
Aisin Seiki Co.,Ltd.
Espec Corporation
Yamato Scientific Co.,Ltd.
Rinnai Corporation
GS-Yuasa Corporation etc.


Contributing to comfortable lifestyles
through hot water

Water heaters are indispensable commodities that support affluent lifestyles. Seiwa has contributed significantly to the evolution and acceptance of electric water heaters. Our technologies have been used in a wide range of applications including the fuel cell systems that are attracting attention as cogeneration systems for residential use, testing and inspection equipment for use in research facilities, and even water heaters for use in aircraft. Here, we introduce just some of these products.

Environmental devices for
industrial applications

We are engaged in the manufacture of various types of environmental equipment including testing and inspection equipment for academic and corporate research institutes, water heaters used in offices and hot water tanks in vending machine, and small-scale water treatment equipment for water purification plants. In addition, we also manufacture industrial hot water tanks, called “Eco Cute” which can provide supply a large capacity of hot water with high efficiency.

Aerospace products

Seiwa manufactures small electric water heaters for aircraft and stainless steel battery cases for defense equipment.

Residential-use products

We have been manufacturing compact household electric water heaters, medium-sized electric water heaters, and “Eco Cute” (heat pump type) water heaters. The hot water storage tanks employed in these products have been manufactured with Seiwa's renowned cylinder welding technology. In addition, we also manufacture reforming units and components for use in fuel cells, which are attracting attention as household cogeneration systems.


Seiwa technologies are backed by
ceaseless day-to-day effort

Thin-sheet stainless steel welding technology that accounts for corrosion resistance and high-temperature strength is an indispensable technology for manufacturing the component parts of fuel cells and water heaters.
In order to create these products, it is important to understand adequately the characteristics of various types of stainless steel materials. In order to accurately reflect the needs of our customers and produce satisfactory products, we have dedicated ourselves to the challenge of constant innovation.

Design and structural analysis

We design various products and perform structural analysis using 3D CAD.
Results from analysis of design verification tests and prototype evaluation are incorporated into product design to deliver high-quality finished products.
We also investigate methods for the optimization of material thickness and welded joints.

Product development grounded in
close cooperation with manufacturers

Our small- and mid-size water heater segment has long benefited from our commitment to excellence in every step from planning to production.
However, we are quickly establishing a record of experience and results in another area as well.
Specifically, we are now combining our special welding technology derived from many years of experience in stainless steel fabrication to the field of industrial environmental devices.
As a result, we are participating in the planning stages of development of environmental testers and test equipment for academic and corporate research facilities.
Moreover, we have become increasingly active in the area of medical applications of stainless steel products.


Quality control and quality assurance

When responding to requests from customers, we put quality first and pay careful attention to all processes from material selection, dimensional precision, and appearance to welding, assembly, and shipment.

Selecting the most suitable stainless steel alloys

Stainless steel alloys with high corrosion-resistance are used in water heater tanks and similar products, but there is a huge array of such materials available.
We accurately assess your needs and help you select the right material in consideration of factors such as usage conditions, processing methods, durability, and cost.

Testing pressure and corrosion resistance

We ensure that we are able to supply reliable products through a variety of quality tests including pressure tests in which the inside of the tank is subjected to high pressure; repetitive pressure tests to estimate the stress life of welds; and corrosion resistance tests, in which the corrosion of welded parts of various stainless steel materials is investigated.


Delivering products that provide peace of mind

We analyze weld strength and corrosion resistance and verify designs through prototype analysis. By reflecting the results of these activities in product design, we are able to supply products that provide customer satisfaction.
The various automatic welding machines, jigs, and other equipment we use in production are made in house.
Seiwa employees put their heart into everything we make, every step of the way from design and analysis to evaluation and the final product.