We have been manufacturing boiler steel tubes and pipes used in all fields, mainly power generation boilers, up to the present day, ever since we first started manufacturing seamless steel tubes for boilers for the first time in Japan in 1912.

During this time, higher temperatures and pressures and larger-capacity boilers have been developed and have undergone rapid technological innovations, together with changes in fuel conditions. Recently in particular, high-efficiency generation has been demanded in order to control total carbon dioxide emissions, from the viewpoint of the worldwide conservation of the global environment, and ultra-supercritical pressure boilers, pressurized fluidized bed boilers, heat recovery steam generators of gas turbine combined cycle, and high-efficiency industrial waste incineration boilers have been constructed one after another, as new thermal power generation boilers. Steel tubes and pipes, to be used to respond to these situations, have been demand to maintain both high quality and high performance. There has also emerged a need for various steel tubes and pipes such as economic steel tubes and specially-shaped steel tubes.

In rapid response to these requests, as an advanced manufacturer of boiler steel tubes and pipes, we have aggressively proceeded with the development of new materials, improvement of production technology, installation of new facilities, and improvement of inspection and quality control technologies.

We are confident that our boiler steel tubes and pipes will fulfill your expectations in every aspect, such as quality, performance, and access to service net-works across various countries

Features

Boiler tubes and pipes require extremely superior quality and a variety of steel grades and dimensions suited to usage situations.

To fully meet these requirements, our boiler tubes and pipes have emerged from a secure system through years of experience and foremost engineering process, as a backdrop.

They are manufactured based on an integrated production system and on strict quality design and quality control, ranging from raw materials to final products.

In line with diversifying needs, we are developing new materials and products, and are conducting a wide variety of research and development, including manufacturing process research.

1. Integrated production system

Our boiler tubes and pipes are consistently controlled, from steel-making to tube and pipe-making, in order to ensure the manufacturing of all steel grades, as well as to assure uniform and stable quality, through strict quality control during each process.

Particularly, steel-making processes, from component mixture to final heat treatment, undergo optimum quality design regarding boiler steel tubes and pipes, by putting years of experience and high engineering process to full use so that products can endure long usage periods of one or two decades. In order to bring the quality design into shape, a new refining method in steel-making is introduced and various manufacturing processes are selected according to dimensions, material properties, and internal and external surface condition.

Seamless steel tubes and pipes are hot manufactured using The plug mill-rolling process, mandrel mill-rolling process, extrusion process, and push bench process.

The plug mill-rolling process is used to manufacture medium-diameter carbon steel tubes and low-alloy steel tubes, and the mandrel mill-rolling process is used to manufacture small-diameter carbon steel tubes and low-alloy steel tubes. The extrusion process is used to manufacture high-alloy steel tubes, such as stainless steel, and special tubes, such as finned tubes. The push bench process is suited for manufacturing large-diameter, thick-wall tubes, and enables the manufacturing of carbon steel, alloy steel, and stainless steel tubes and pipes.

These hot manufactured tubes are cold finished using cold-drawing and cold-rolling processes that fit the applications and thermal treatments.

2. Quality assurance system

Boiler tubes and pipes are strongly demanded in order to satisfy especially strict usage conditions, along with operational reliability. We conduct strict quality control in all processes, from steel-making to tube and pipe-making, and we have established the following quality assurance system.

①Independence of the quality assurance department

The quality assurance department is independent from the manufacturing department and has primary authority and responsibility concerning quality in order, to take charge of ensuring such quality.

②Standardization of tasks

Various tasks related to manufacturing and quality are standardized and documented for unification.

③Adoption of a inspector qualification system

All inspections engaged in work affecting quality have received strict training and have passed a qualification test.

④Full adoption of nondestructive tests

Various required tests and inspections are conducted according to applications, and nondestructive tests are applied to all products in the final inspection.

⑤Establishment of periodic gauges and tester calibration systems

Various gauges and testers are periodically calibrated to ensure quality inspection.

3. Research and development system

Our boiler tubes and pipes have been used the world over, embodying various characteristic products through distinguished engineering process and abundant experience, and they have earned high reputation and trust not only in Japan but also overseas.

It is no exaggeration to say that this is also a good result of systematic research and development systems, ranging from raw materials to products.

At present, with the aim of a further leap forward, we are proceeding with research from the following broad angles.

• Research on high-temperature creep strength properties
• Research on high-temperature corrosion protection materials
• Research on coal-fired steel tube materials
• Research on weldability and workability
• Research on manufacturing processes for quality stability
• Research on nondestructive inspection and measurement technologies

We will also further improve the research department and enhance its functions, and will strive to help promote global iron-making in future