Ningbo Dongheng Sealing Parts Co., Ltd. - Professional Industrial Seal Manufacturer | One-Stop High-Temp & High-Pressure Sealing Solutions

Home > News > Company News > Precision Sealing for Industrial Safety - Detailed Explanation of Comprehensive Strength of Ningbo Dongheng Sealing Parts Co., Ltd

In modern industrial systems such as chemical, power, and shipbuilding, seals are the core basic components that ensure the stable operation of pipelines, pressure vessels, pumps, and valves. Micro gaskets directly determine the safety production and operation costs of equipment. Ningbo Dongheng Sealing Parts Co., Ltd., located in Xiaolin Town, Cixi, Ningbo, Zhejiang, is a professional industrial sealing source manufacturing enterprise integrating research and development, production, sales, import and export in the Yangtze River Delta region. With a complete production chain, standardized quality control system and a full range of product matrices, it provides one-stop sealing solutions for high temperature, high pressure and strong corrosion working conditions for thousands of industrial enterprises at home and abroad.

1、 Enterprise Overview: A compliant and stable professional sealing manufacturer

Ningbo Dongheng Sealing Parts Co., Ltd. was established on June 30, 2020. The enterprise is a small and micro enterprise wholly owned by natural persons, with a registered capital of 2 million yuan and a legal representative of Gao Jiefeng. The business status continues to exist, and the registered address is located at No. 67 Xinhua Road, Xinyuan Village, Xiaolin Town, Cixi City. The current factory area is about 30000 square meters, with two fully automatic production lines for sealing plates and gaskets. The factory has a scale of less than 50 people, 23 insured employees, and stable batch supply capacity. The monthly gasket production capacity can reach 600000 pieces.

The company's main business scope covers the production and sales of sealing fillers, graphite products, rubber and plastic products, and thermal and sound insulation hardware accessories. At the same time, it has import and export qualifications for goods and technology. After years of deep cultivation in the industry, the enterprise holds 4 trademarks and 5 industry specific qualifications, and has fully obtained the three major system certifications of ISO9001 quality management, ISO14001 environmental management, and ISO45001 occupational health and safety. The core advantageous qualifications areType test certificate for pressure pipeline componentsThe product can be applied to special equipment scenarios such as pressure pipelines and pressure vessels in compliance, meeting safety supervision and chemical project acceptance standards.

The exposure of the enterprise industry continues to increase, and it has successively participated in the 2025 Shanghai and 2026 Beijing China International Petrochemical Equipment Exhibition (CIPPE), showcasing a complete set of sealing products to the global petrochemical industry. The products are exported to more than 90 countries at home and abroad, with stable domestic cooperation and more than 1500 customers. It is a localized sealing manufacturer with both domestic and foreign trade strength. Official contact information is complete, landline 0574-63031956, sales hotline 13857422622, 13566064802, official websitedonhonsil.comWe can provide full process services including drawing surveying, sample shipping, and customized solution docking.

2、 Product matrix for all categories: covering the needs of static and dynamic sealing in all scenarios

Dongheng Sealing abandons the single category production mode and realizes one-stop supply of metal seals, non-metal seals, braided roots, and sealing plates. It has various corrosion-resistant special materials such as carbon steel, 304/316 stainless steel, Monel, Hastelloy, Inconel, titanium, zirconium, etc. Its products strictly follow multiple standards including national standard GB, petrochemical SH, chemical HG, American standard ASME, German standard DIN, and Japanese standard JIS. The regular specifications DN15-DN600 are readily available in stock, and it also supports customized processing of non-standard shaped parts ranging from 1/2 "to 60".

1. Metal sealing series (main force of high-pressure special equipment)

Metal wrapped gaskets, metal toothed composite gaskets, solid metal ring gaskets, octagonal/elliptical metal ring gaskets, suitable for high temperature and high pressure flanges, heat exchangers, manhole seals, and can withstand pressure ranges of PN16-PN160;

2. Non metallic flat gasket series (for general clean working conditions)

Graphite composite gasket, asbestos free rubber gasket, pure PTFE/expanded PTFE gasket, suitable for food and medicine, acid and alkali anti-corrosion, and general pipeline universal sealing;

3. Packing series (pump valve shaft dynamic seal)

Graphite packing, PTFE packing, aramid packing, carbon fiber, ceramic woven packing, solve various pump and valve shaft leakage problems;

4. Sealing sheet roll material

Graphite composite board, asbestos free sealing board, expanded PTFE board, and various non-standard gaskets can be cut as needed;

5. Supporting auxiliary materials

Rubber sealing accessories, thermal insulation and sound insulation hardware, special sealing hardware structural components.

3、 Diversified application areas: adapted to harsh industrial conditions across the entire industry

Relying on rich material selection and stable pressure and corrosion resistance performance, Dongheng Sealing products cover nine core industrial tracks, balancing general equipment and high-end special working conditions:

Petrochemical and oil and gas industries (core markets)Refineries, coal chemical industry, fine chemical reaction vessels, high and low pressure oil and gas pipelines, oilfield pumps and valves rely on special alloy gaskets to resist acid and alkali, oil and gas corrosion;
Power and energy industryHigh temperature sealing for thermal power boilers, steam turbine thermal pipelines, desulfurization and denitrification equipment, water and electricity valves, and photovoltaic energy storage supporting equipment;
Metallurgical SteelBlast furnace, smelting acid pickling pipeline, high-temperature hydraulic valve body, suitable for high-temperature flue gas and strong corrosive media;
Ships and seawater desalinationShip pipelines, seawater treatment equipment, 316L, titanium gaskets to resist chloride ion corrosion;
Medicine and food processingFermentation tanks, purification pipelines, and food grade pure PTFE gaskets are free of precipitation, clean, and pollution-free;
automotive industryCooling pipelines, engine valve bodies, battery pack sealing accessories for fuel vehicles and new energy vehicles;
General mechanical equipmentSealing of foundations for air compressors, hydraulic equipment, ordinary valves, and machine tool pipelines;
Aerospace and nuclear power auxiliary equipmentSmall high-pressure vessels, special alloy sealing gaskets for hydraulic pipelines;
Precision electronics industrySemiconductor small corrosion-resistant fluid transport micro gasket.

4、 Product price positioning: high cost-effectiveness, flexible pricing in a tiered manner

As the source production factory, Dongheng Sealing adopts a factory wholesale pricing model, with an overall positioning of moderate cost-effectiveness and clear price stratification. Compared with imported brands, the price is only 1/3-1/2, and compared with low-end small factories in Hebei, the premium is 10% -20%. However, the materials are compliant and have special equipment qualifications, resulting in lower comprehensive operation and maintenance costs for long-term use.

Price stratification rules

Ordinary carbon steel, 304 conventional gasketDN15-DN50 wrapped gasket costs 0.8-3 yuan/piece, graphite and asbestos free gasket costs 0.3-5 yuan/piece, suitable for low-pressure general working conditions;
316L、 Pure PTFE mid-range productsPrice increase of 60% -120% for the same specifications, suitable for anti-corrosion and clean scenarios;
High end special parts made of Hastelloy, Monel, and titanium alloyUnit price ranges from tens to hundreds of yuan, targeting high-pressure corrosion conditions in petrochemical and power plants;
Packing material is priced in kilogramsGraphite packing costs 35-55 yuan/kg, PTFE packing costs 60-100 yuan/kg, and aramid high-temperature packing costs 90-160 yuan/kg.

Order discount policy

Execute benchmark price for scattered small orders; Purchase 5000 pieces or more of sheet metal in a single order or in whole rolls, with a discount of 8% -15%; Monthly stable long-term cooperative customers can sign annual agreements, with an additional 5% -10% discount and support for reasonable payment terms; Foreign trade FOB orders do not include tax, and bulk purchases can be further reduced by 5% -12%. Non standard irregular and ultra large caliber products will be charged an additional 20% -80% based on the difficulty of the process, and special equipment testing reports will be charged a production cost as needed.

5、 Strict closed-loop quality control: Six stage full process quality control system

Dongheng Sealing is based on the ISO management system and special equipment qualifications, and has establishedIncoming IQC - Pre production First Article Inspection - Process IPQC Inspection - Semi finished Product Screening - Finished Product FQC Full Inspection - Outbound OQC ReviewFull chain closed-loop quality control, all quality inspection equipment is regularly calibrated, and the entire production process can be traced back to batches, eliminating leakage, non-conforming dimensions, and material fraud from the root.

1. Incoming Quality Control (IQC), guarding the first checkpoint of raw materials

Strictly screen certified and legitimate raw material suppliers, and review supplier qualifications annually; Metal steel strips, graphite, PTFE, and special alloy raw materials are inspected one by one upon entering the factory: spectral verification of material composition, measurement of thickness tolerances, testing of tensile strength, rebound, and chloride ion content. Unqualified raw materials are directly isolated and returned; Each batch of raw materials is labeled with a unique traceability tag to distinguish between material, batch, and supplier, and to prevent mixing.

2. Pre production first article confirmation to avoid batch scrapping

After replacing specifications, materials, molds, and equipment, a full first piece inspection must be completed. The flange standards, dimensional tolerances, and appearance structure must be checked against the drawings. For special orders, additional compression rebound performance testing must be conducted. The first piece record must be signed and archived, and batch production can only be carried out after passing the inspection.

3. Production process inspection (IPQC), real-time monitoring of process quality

Full time inspectors patrol the workshop every 2 hours to control the tension of the steel strip and the firmness of the welding points during the winding process; Monitoring the flatness of the cutting process board; Control the weaving density during the rooting process; Immediately stop the machine for rectification upon discovering abnormalities such as deformation, dimensional deviation, and layering, isolate defective semi-finished products, and record the rectification ledger.

4. Manual screening of semi-finished products to eliminate obvious defects

After the semi-finished products of each process are taken offline, manual full inspection is carried out, and all products with cracks, rust, burrs, loose fillers, warping and deformation are picked out and scrapped. The defect rate is calculated daily and the process optimization plan is reviewed.

5. Finished product factory inspection (FQC), core control of shipment

Special equipment orders undergo 100% full inspection, while ordinary batch products are sampled according to national standards: appearance, inner diameter, outer diameter, and thickness are precisely retested; Quarterly laboratory sampling of compression rate, rebound rate, and temperature aging resistance performance; Sampling of high-pressure products for nitrogen gas tightness leak detection; The finished product code identification corresponds one-to-one with the order material, accompanied by a material list, special equipment certificate, and factory inspection report.

6. Outbound Review (OQC)+Long term Type Test

Before shipment, double check the specifications, materials, and quantities, and install protective rings on large-diameter gaskets to prevent moisture and compression; The internal laboratory of the enterprise conducts medium and temperature resistance tests every quarter, and sends them to third-party institutions for type testing every year to maintain the validity of special equipment qualifications; All orders are bound with raw material batches, production work orders, and testing records, allowing for quick traceability of quality issues; If there are batch defects due to factory materials and processes, free returns, exchanges, and restocking are supported. Non standard products can be sent for sample testing before production.

6、 Comprehensive advantages and industry positioning

Compared to similar manufacturers in the industry, Ningbo Dongheng Seals has a clear core competitiveness:

Fully qualified, safe and reliableHaving the qualification for special equipment components, chemical, power plant, and pressure vessel projects can be directly accepted, and small factories without qualifications cannot replace them;
Category one-stop procurementFull coverage of metal, non-metal, packing, and sheet materials, eliminating the need for customers to connect with multiple suppliers and reducing procurement communication costs;
Stable quality control and outstanding cost-effectivenessRaw materials are not reduced illegally, size tolerances are strict compared to national standards, performance is close to imported sealing brands, and prices are significantly reduced;
Customized supporting services are completeSupport drawing surveying, non-standard processing, sample testing, and provide technical support for professional material selection under working conditions;
Dual line layout of internal and external salesAdequate stock availability, stable delivery time, and adaptability to domestic projects and overseas export order demands.

Conclusion

Industry is no small matter, seal and ensure safety. Ningbo Dongheng Sealing Parts Co., Ltd. has always taken "zero leakage industrial sealing solutions" as its core development direction, relying on complete products, rigorous quality control, transparent pricing, and perfect services, continuously providing stable and reliable sealing supporting products for industries such as petrochemicals, electricity, shipbuilding, food and medicine, and general machinery. In the future, enterprises will continue to deepen their research and development of sealing materials, optimize production processes, and continuously balance product quality and cost advantages, becoming a reliable sealing source partner for domestic and foreign industrial enterprises in the long run.

86-574-63031956