World’s smallest calibre seamless pipe mill developed by CISDI

—CISDI supplied the initial package equipment to Fengbao Pipe Industry, China

The world’s smallest calibre 3-roll pipe mill has begun production in China.

The Φ89mm multi-stand pipe mill at Fengbao Pipe Industry in Linzhou, Henan province, was started up on December 19.

It was developed and package-supplied by CISDI and its main technical indicators have surpassed those of similar mills around the world.

The mill is automatically controlled to a high level and produces in an intelligent way. The final pipe product is of high dimensional accuracy, with minimal deviation of wall thickness. Surface quality is good and cutting loss is minimal.

The project marks the transformation from traditional cold rolling or cold drawing to hot rolling process for the production of small-calibre seamless pipe. It also sets a benchmark for successful upgrading in the ongoing quest for greener and more intelligent manufacture.

A tailor-made, advanced, high-performance, green and intelligent seamless pipe mill

The Fengbao pipe mill is the world’s first mandrel mill capable of producing pipe to calibre specifications of Φ32~Φ89mm and wall thicknesses of 3-12mm.

The mill has been transformed from traditional cold rolling methods to hot rolling. It will supply high-end seamless steel pipes for mechanical, energy and petroleum industries and has an annual capacity of 200,000 tonnes.

CISDI designed and engineered the complicated transformational project, which increases the plant’s market competitiveness and cut its emissions.

It delivered the process, equipment, hydraulic, electric and automation and L2 control model, from mandrel mill to cooling bed.

Fengbao’s production method is now setting a trend for manufacturing pipe mill in an environmentally friendly way.

Waste acid from the traditional piercing and cold rolling process pollutes the environment

Hot-rolling small-calibre pipe not only solves the pollution problem but also delivers high-precision, high-quality products.

During the project, CISDI’s high-speed data acquisition and monitor system gave intelligent diagnosis of process and production and 3D design and CAE modelling simulation optimised structures and design, equipment strength and rigidity.

Fengbao’s automation control level is now world-leading. It has achieved a roll position precision control range of ±2μm. The mill’s hydraulic roll gap control system is high-precision and has a quick response.

It is China’s first reference of mandrel mill control model and tension reducer control model, which creates an organic integration between process model and automation control.

The tension reducer control system can regulate the rotation speed of 100rpm by as little as 0.1 second. It can achieve online self-learning and automatic control, remarkably improving the mill’s intelligence levels.

Productivity has been greatly enhanced by the high-speed mandrel retainer’s precision control technology, which enables rolling piece rates of up to 120 pieces per hour.

CISDI designed dedicated tools and dies by means of non-linear heavy plastic deformation finite element analysis. These tools and dies enabled rolling grooves to be accurately tailored, thus ensuring high surface quality and dimensionally-precise small-calibre pipe-rolling.

Other major achievements:

Mandrel mill low cutting loss control technology means the sharpening rolling has been finally achieved on mandrel mill.

Head and tail end dynamic tension compensation control has been actualised on the tension reducer.

A significant reduction in the cut end length, which contributes to a 1~2 per cent higher metal yield.

Automation soft power creating Chinese speed records

As early as in the beginning of this century, China’s equipment manufacturers set out to produce Chinese-made mandrel mill equipment.

But the restrictions of process and control models meant steel plants had no option but to rely on past production data for guiding production. This often destabilised equipment-running, reducing product acceptance rates and increasing production costs.

Engineering specialists CISDI link applied science with project practice and have established a scientific and innovative eco chain for developing core technology and product serialisation - from theoretical study to lab research, pilot, design and operation. Our own manufacturing base, CISDI Equipment Co. Ltd., is one of China’s top platforms for production and research, playing dual roles for pilot and manufacture. We are focussed on creating products and techniques which improve industrial competitiveness and applying our core technology to products and equipment.

During the research, development and design phases of our project at Fengbao pipe mill, our engineers analysed the precision and strength of critical parts of the mill’s equipment and foresaw a manufacturing bottleneck.

They acted as manufacturing supervisors and communicated with frontline workers as they coordinated machining process optimisation and flow and refined quality control.

All main equipment was pre-assembled offsite to shorten installation and commissioning time and avoid problems on-site. During the installation and commissioning phase engineers were stationed on-site to track and supervise. Laser calibration ensured the precision of the installation of final equipment.

The core system of mill is electric and automation-driven and has been nicknamed the mill’s ‘soft power’. Standardised software libraries for mill hydraulic roll gap control, drive control and medium system control have greatly improved the efficiency of equipment software programming and commissioning.

Software and hardware platforms were fully tested in the lab before commissioning. This also allowed engineers to master the equipment parameters, indicators and commissioning plans, which resulted in a smooth commissioning and start-up.

It took just 20 days to complete the individual and combined commissioning of full-line equipment and successfully pass the final hot test. This super-fast time could be a Chinese record.

The project’s success highlights the many advantages of CISDI’s core equipment. Since the hot test, the mill equipment has been running stably and in under three months has ramped up production to meet the designed figures - another Chinese speed record.

The first piece of red pipe is rolled out from the world’s first Φ89mm 3-roll mandrel mill during the hot test

Mill equipment at the world’s first Φ89mm 3-roll mandrel mill