News Details

1、 Technical Standards and Material Characteristics: Performance Breakthrough of APIDN80 Steel Grade

As the core component of oilfield specific pipes, the APIDN80 oil drilling hose strictly follows the API 5CT specification in terms of technical standards. The steel grade N80 represents a material yield strength of 80000 psi (approximately 552 MPa), far exceeding the bearing capacity of ordinary carbon steel. This steel grade significantly improves its creep resistance under high temperature conditions by optimizing the alloy composition design and adding elements such as manganese and molybdenum to the carbon steel matrix. For example, in the ultra deep well operation of Tarim Oilfield, N80 steel grade casing can still maintain structural integrity at a high temperature of 150 ℃, and its anti extrusion strength is increased by more than 30% compared to J55 steel grade.

 

The impact resistance of carbon steel joints is achieved through heat treatment processes. Taking the products of Hebei Baoji Pipeline Manufacturing Co., Ltd. as an example, their joints adopt carburizing and quenching technology, with a surface hardness of HRC58-62 and a core toughness maintained in the HV200-250 range, forming a gradient structure of "external hardness and internal toughness". This design enables the joint to resist surface wear and avoid brittle fracture when subjected to drilling impact loads. In a field test in a certain block of Shengli Oilfield, this type of joint worked for more than 2000 hours under continuous impact load, and the failure probability was reduced by 65% compared to traditional joints.

 

The composite structure of the hose and joint further enhances the overall performance. The technology of Shandong Deni Metal Manufacturing Co., Ltd. shows that by embedding a spiral carbon fiber reinforcement layer in the inner layer of the hose and using chloroprene rubber and aramid fiber composite coating on the outer layer, the hose can maintain a burst pressure of over 10MPa at a high temperature of 300 ℃. This structure performs well in shale gas extraction in the Sichuan Basin, with the service life of a single hose extended by 40% compared to traditional products.

 

2、 Oilfield application scenario: reliability verification under extreme working conditions

In ultra deep well drilling, the APIDN80 hose system needs to address multiple challenges. Taking a certain offshore platform in Bohai Oilfield as an example, its well depth reaches 5500 meters, the geothermal gradient is 3.5 ℃/100 meters, and the peak temperature of drilling fluid reaches 180 ℃. After using N80 steel grade casing from Tianjin Longkailai Petroleum Equipment Co., Ltd., zero leakage of the casing string under high pressure differential environment was achieved through special thread connection technology (such as TP series airtight thread). On site monitoring data shows that under an internal pressure of 120MPa, the micro motion wear of the threaded sealing surface of the casing is less than 0.01mm/year.

 

High sulfur gas fields have higher requirements for the corrosion resistance of materials. In the exploitation of Puguang gas field, under well conditions with a hydrogen sulfide content of up to 15%, a casing system composed of 13Cr material and N80 steel grade is used, and the corrosion rate is controlled within 0.03mm/year by surface nickel phosphorus alloy treatment. The matching carbon steel joint adopts bimetallic electroplating process, with nickel plating on the inner layer to prevent sulfide corrosion and chrome plating on the outer layer to improve wear resistance. After continuous operation for 18 months, there were no pitting corrosion pits on the surface of the joint.

 

In geothermal well drilling, the temperature resistance of the hose system becomes crucial. In the Tengchong geothermal field in Yunnan, the bottom hole temperature reaches 280 ℃. Using PTFE lined hoses from Shandong Yitai Hydraulic Technology Co., Ltd. and N80 steel grade joints, safe transportation of high-temperature steam is achieved. The system effectively absorbs axial displacement caused by temperature changes and avoids the risk of seal failure by installing a thermal expansion compensation ring at the joint.

 

3、 Manufacturing process and quality control: full process digital management

The production of APIDN80 hose fittings requires 12 critical processes. Taking the process of Cangzhou Dahai Pipeline Co., Ltd. as an example, the raw materials are refined steel billets by electric furnace, and seamless billets are made through continuous casting and rolling process, and then cold drawn to the target size. The joint thread processing adopts a CNC rolling machine, combined with an online eddy current inspection system, to ensure that the thread profile accuracy reaches 0.01mm level. The heat treatment process adopts a controllable atmosphere furnace, which precisely controls the heating rate and insulation time to homogenize the material structure.

 

The quality control system covers 100% testing from raw materials to finished products. Wuxi Yingxin Steel Industry Co., Ltd. has introduced an AI visual inspection system, which has achieved an accuracy rate of 99.8% in identifying surface defects on hoses. The joint thread is inspected for full size using a coordinate measuring instrument to ensure that parameters such as pitch diameter and taper comply with API 5B standards. Mechanical performance testing includes full-scale physical blasting tests and fatigue life tests. For example, the products of Liaocheng Kuncheng Pipe Industry Co., Ltd. need to pass 200000 cycles of loading tests, and the fatigue strength should not be less than 80% of the base metal.

 

The digital traceability system has achieved full lifecycle management. Fengbao Petroleum Equipment Co., Ltd. in Jinghai District, Tianjin, equips each hose with an RFID chip to record over 200 data items, including raw material batches, heat treatment curves, and non-destructive testing reports. In the application of Changqing Oilfield, the system has shortened the fault location time from an average of 72 hours to 4 hours, and improved the accuracy of spare parts matching to 100%.

 

conclusion

The APIDN80 petroleum drilling hose carbon steel joint system has built a technical system that adapts to extreme working conditions through material innovation, process optimization, and digital control. From ultra deep wells to high sulfur gas fields, from geothermal development to ocean drilling, its performance has verified the deep integration of API standards and domestic technology. In the future, with the advancement of intelligent oilfield construction, the system will further integrate sensors and adaptive control technology to provide more reliable equipment support for oil and gas extraction.