Recently, Heilongjiang Jianlong independently developed a 110TS (Φ177.8mm×12.65mm) high hydrogen sulfide corrosion resistance and crush resistance casing, and completed the entire process trial production. Steelmaking, hot rolling, heat treatment, and internal and external inspection were completed in one go, marking that the domestic supply of 110ksi-grade sulfur-resistant special pipes has become more feasible.

Thousands of meters underground, hydrogen sulfide and high pressure are among the most challenging conditions encountered by oil casing – hydrogen atoms penetrate the interior of the steel, causing the pipe to gradually become brittle; the formation pressure squeezes from the outside, causing the pipe wall to gradually become unstable. Compared to ordinary casing, 110TS steel grade products have almost stringent requirements for material purity, strength and toughness matching, sulfur resistance stability and dimensional accuracy control, making them a high-end product with extremely high technical content in the oil and gas pipe field.

Targeting the industry's high-end and essential needs, the Heilongjiang Jianlong technical team has conducted targeted research and development on specialized steel grade systems. Through precise alloy ratios and extreme composition control, they have constructed exclusive material solutions adapted to extreme working conditions: relying on chromium to improve overall hardenability and achieve uniform and stable microstructure throughout the steel pipe; using molybdenum to enhance high-temperature tempering stability and solidify the safety baseline under high-strength working conditions; and employing vanadium and niobium composite microalloying technology to precisely balance strength and toughness indicators, thus resolving the industry contradiction of "high strength but brittleness, high toughness but weak strength" in high-end pipes.

To ensure reliability under extreme operating conditions, the project team significantly tightened internal control standards, keeping harmful impurities such as phosphorus and sulfur at extremely low levels far superior to those of conventional steel grades, thus avoiding the risks of hydrogen-induced cracking and corrosion failure from the source.

To achieve stable mass production and controllable consistency, Heilongjiang Jianlong has established a rigorous quality control system for the entire process: improving the purity of molten steel through double-slag tapping in the converter and refining with LF white slag; ensuring uniform billet structure by relying on continuous casting electromagnetic stirring and constant casting speed processes; avoiding micro-damage inside the pipe by adopting a damage-free mandrel rolling process; and in the core tempering heat treatment process, innovatively adopting a three-stage precise temperature control + four-process linkage control mode to effectively offset the interference of gas calorific value fluctuations, accurately locking and stabilizing the yield strength of the product, and achieving "batch consistency and high-quality products" for high-end casing.

Tests showed that the new product, loaded with 80% SMYS according to NACE TM0177 standard A method, remained unbroken for 720 hours; the hardness in all four quadrants of the full wall thickness did not exceed the upper limit of 29 HRC specified in the technical agreement; the resistance to external extrusion and the resistance to blasting were superior to the requirements of the technical agreement, and the safety redundancy under extreme working conditions was sufficient, making it fully suitable for high sulfur content and high-pressure deep oil and gas extraction scenarios.

Next, Heilongjiang Jianlong will continue to deepen its expertise in the field of sulfur-resistant pipes, transforming its trial production experience into a stable supply capacity of high-end products, contributing to the localization of energy equipment, and injecting a continuous stream of "Jianlong power" into the construction of a quality-strong nation.