The outer protective layer is mainly made of high-strength and high-toughness polyethylene material, and adopts the company's core polyethylene modification technology, which polarizes the surface of polyethylene and greatly improves its adhesion performance with polyurethane.

1.Working steel pipe:seamless steel pipe,spiral welded pipe,straight seam welded pipe;before thermal insulation,the mechanical rust removal level is not lower than GB/T8923.1 Sa level 2.5 level in.
2.Slepipe:the special modified flam retardant and anti static polyethylene resin processed by single screw extrusion machine,which has the characteristics of good impact resistance,isolation effect and corrosion resistance.
3.Polyurethane insulation layer:uesing modified flame retardant  polyurethane foam by high pressure injection material,fill the gap between the casing and the working steel pipe,play the most important insulation effect,with the characterisics of low thermal conductivity,high compression strength,low water absorption,high closure rate.

Insulation steel pipes are used in liauid and gas transmission pipe insulation projects in petroleum,chemical,central heating and heating networks,central air-conditioning ventilation pipes,and municipal engneering.High-temperature prefabricated direct-buried thermal insulation steel pipe is a direct-buried prefabricated thermal insulation steel pipe with good thermal insulation performance,safety and reliabllity,and low construction cost.

Shandong Donghong Pipe Industry Co., Ltd. (referred to as: Donghong Co., Ltd., stock code: 603856) is headquartered in Qufu, China, the hometown of Confucius.Is an engineering pipeline manufacturer, pipeline engineering service provider and pipeline engineering general contractor with the main business of four categories of functional and customized pipelines: special pipelines for rainwater and sewage diversion, special pipelines for municipal areas, special pipelines for industrial and mining areas, and special pipelines for national key engineering projects. The company has built up an industrial ecosystem with the participation of design institutes, financial institutions,  port logistics, construction units, upstream and downstream enterprises, etc. The company is committed to becoming a global leading pipeline system comprehensive solution provider by making intelligent pipelines change human life and constant safety of pipeline transportation.

Donghong has more than 200 R&D personnel and more than 100 patents. Relying on national enterprise technology  center, national CNAS laboratory, academician expert workstation, post-doctoral workstation and other national technology R&D platforms, Donghong deepens the research on digitalization, informatization and intelligentization of pipeline engineering and leads the development of engineering pipeline industry.
Donghong was listed on the main board of Shanghai in November 2017, becoming the first main board-listed company in China's engineered composite piping system.

Relying on national technology research and development platforms such as National Enterprise Technology Center, National CNAS Laboratory,  Academician Expert Workstation, Post-doctoral Workstation, etc., Donghong deepens the research on the digitization, informatization and intelligence of pipeline engineering, leads the development of engineering pipeline industry, and serves the national key strategic projects and people's livelihood projects, such as South-to-North Water Diversion, Huangzhilin, Hanzhiwei, Beijing-New Zealand Expressway, One Belt, One Road, "Two Clear and One Tip", standardized farmland, urban and rural water supply integration, Liren gas, centralized heat supply, etc. The company has been engaged in national key strategic projects and people's livelihood projects.

Excellent technical research and development capability.
We have a national CNAS laboratory, introduce advanced test equipment, cooperate with the development of new products, new materials, new types of connections, and rigorous testing of our own products to ensure stable and reliable product quality.

Donghong has established strategic partnerships with more than 5 5A-level logistics companies, and we have many years of transportation experience. Combining automobile transportation, railway transportation, port and shipping logistics, etc., no matter the heat or cold, no matter the area is remote or harsh, we can provide you with the best service. We have a comprehensive transportation strategy to ensure that every shipment is delivered to the customer site as soon as possible.

1. Is your product meets the international standard ?
Our products have pass CE, BV, ISO and wars certificate, and all figures indicates higher than standard, you can feel free to let us know which national standard you required, we will check or test it for you.

2. What kind of service do you offer ?
As a manufacture fatory, we provide pipe products, pipe fittings, package and shipping; as a professional consulation company we provide project consulting advise, pipe system solutions and design suggestions; as an engineering focused enterprise , we also provide pipeline contractor service and pipe repair service, also can give free maintance guidance.

3. Do you support OEM/ODM service?
Yes, we offer customization in material, specification, logo, package , connection methods andothers. Meanwhile, our professional team can offer solution suggestion for your specified projects, we have successfull cases of that service.

4. What's your terms of payment?
T/T or L/C at sight.

5. How can you gurantee the goods you offered is qualified?
We warmly welcome all customers arrange the visit to our company and see our goods in sight, we can also provide strict test as per customer required before order. Meanwhile, before the bulk production, we can dispatch samples for customer to do their own tests to qualify the products.