I. Product Overview

The Molybdenum Piercer Point is an indispensable core high-temperature tool in modern hot-rolling seamless steel tube production, widely used in piercing mill units.

• Functional Role: During the cross-roll piercing process, it is mounted on the front end of the pusher rod of the piercing mill. It is thrust at high speed and with great force against a solid round billet heated to forging temperature in a furnace, penetrating it in one action to form a hollow thick-walled shell.
• Core Value: As the component that directly contacts the high-temperature billet and withstands the most severe working conditions, its performance directly determines the stability of the piercing process, the internal surface quality of the steel tube, and the production efficiency and cost per tool unit.

II. Core Technical Features

The exceptional performance exceptional performance of the molybdenum piercer point stems from the unique physical and chemical properties of molybdenum metal and its alloys, primarily demonstrated in the following aspects:

Exceptional High-Temperature Strength and Hardness

• Molybdenum has a very high melting point (2620°C), far exceeding that of steel. Even at service temperatures ranging from 1000°C to 1300°C, the molybdenum piercer point can maintain significantly higher strength and hardness than ordinary alloy tools, offering strong resistance to plastic deformation, thereby ensuring precise dimensions of the pierced shell.

Excellent Anti-Thermal Shock Fatigue Performance

• Piercing operation is a typical intermittent production process, where the piercer point undergoes cyclic shocks from room temperature to over a thousand degrees Celsius within extremely short time frames. Molybdenum material possesses good thermal conductivity and moderate toughness, which can effectively mitigate the accumulation of thermal stress and prevent cracking or spalling caused by rapid heating and cooling, greatly extending its service life.

Outstanding Wear Resistance and Oxidation Protection

• When contacting the high-speed rotating, heated billet, the working surface of the piercer point endures severe abrasive and adhesive wear. Its microstructure can be further densified through specialized spinning or forging processes to enhance wear resistance.
• To prevent rapid oxidation of molybdenum at high temperatures, the working surface of the piercer point is typically coated with a high-temperature-resistant glass lubricant layer or undergoes special metal diffusion treatment. This protective film acts both as a barrier against air and as a friction-reducing lubricant.

Superior Thermal Stability and Long Service Life

• Compared to traditional alloy steel piercer points, the molybdenum piercer point is less prone to softening and phase transformation at high temperatures, exhibiting stable microstructure. Consequently, its average service life can be increased severalfold to dozens of times, effectively reducing downtime for tool changes on the production line and improving overall economic efficiency.

III. Typical Application Areas

The molybdenum piercer point is essential for producing high-performance and high-difficulty seamless steel tubes. Its main applications include:

• Core Scenario: Various types of piercing mills in modern seamless steel tube plants, especially two-roll (Mannesmann type) and three-roll (Assel type) cross-roll piercing mills.
• Key Material Production: It is almost the only reliable choice when piercing special types of seamless tubes made from materials such as high-alloy steel, stainless steel, heat-resistant steel, bearing steel, and tool steel, which have high deformation resistance and strong high-temperature adhesion.
• High-End Product Manufacturing: Widely used in manufacturing oil country tubular goods (OCTG) for petroleum drilling, high-pressure boiler tubes for petrochemical plants, high-grade piping for supercritical/ultra-supercritical power generation units, and other mechanical structural tubes demanding stringent internal quality.