How to deal with the oxide skin produced on the surface of seamless steel pipe

The seamless pipe has a hollow cross section and is widely used as a pipeline for transporting fluids, such as octg casing for transporting oil, natural gas, gas, water, and certain solid materials. Compared with round steel, seamless pipe has higher bending and torsional strength and better compressive capacity, and is an economical section steel. The steel pipe dimension is expressed in millimeters of outer diameter * wall thickness.

During the use of seamless steel pipes, the oxide film on the surface is not easy to fall off. Typically, oxide films are produced in a furnace. So how to clean the oxide film on the surface of the seamless steel pipe?

1. Scale cleaning machine treatment

Scale cleaning machine is mainly composed of steel brush roller, driving device, high pressure water system, cooling water system and clamping device. Two rollers with steel wires (called steel brush rollers) are installed on the roller bed. The steel brush rollers rotate at a high speed in the opposite direction of the slab running, and the steel wires scour the surface of the slab to remove the iron oxide scale attached to the surface of the slab. .

Scale cleaners are suitable for many steel grades, but cannot clean scale thoroughly enough.

2. Water explosion pool

The water explosion pool uses circulating water at normal temperature as the cooling medium, puts the high-temperature casting slab into the pool, and uses "water explosion" to remove the oxide skin on the surface of the casting slab. The principle is that when water encounters a high-temperature billet, it vaporizes instantly, resulting in a "water explosion" and a large amount of high-pressure steam. The impulsive force of the steam acts on the surface of the cast slab to peel off the iron oxide scale. At the same time, the slab and the scale on its surface are cooled rapidly at high temperature, resulting in shrinkage stress. Due to the differential stress between the slab and its surface, the scale breaks and flakes off.

3. Clean the shot blasting machine.

Shot blasting machines are often used to clean the scale on the surface of the slab. The shot blasting machine is mainly composed of a shot blasting chamber, a shot blasting head, a shot blasting conveying system, a shot blasting cleaning device, a shot blasting supplementary device, a dust removal system, a lubrication system and an electrical control system. Its working principle is to use the high-speed steel projectiles thrown by the shot blasting machine to impact the oxide scale on the surface of the slab to make it fall off.

The shot blasting machine has a high operating rate, and the cleaning speed can reach 3 m/min. There are many kinds of steel materials that are suitable for use. The iron oxide scale removal effect is good. However, the shot blasting machine cannot handle high-temperature casting slabs, and the temperature of the casting slabs is generally required to be lower than 80. Therefore, the shot blasting machine cannot be used to clean the scale of the cast slab online, and the cast slab needs to be cooled below 80°C for shot blasting.

Strengthening the maintenance of seamless steel pipes during use can effectively prolong the service life of seamless steel pipes.

1. Ensure that the warehouse or site where seamless steel pipes are stored is clean and hygienic, the ventilation and drainage are smooth, and the ground is free of weeds and sundries.

2. Make sure that the seamless steel pipe is not put together with harmful substances and materials. Corrosion reactions can easily occur if mixed.

3. Do not mix seamless steel pipes with other building materials to avoid pollution caused by different materials.

4. Large seamless steel pipes cannot be placed in warehouses, but the storage site must also meet the above conditions, and stone or wooden boards are placed at the bottom of the seamless steel pipes to isolate them from the ground.

5. Be sure to keep the venue ventilated and waterproof.

Article source: https://article-realm.com/article/Business/44413-How-to-deal-with-the-oxide-skin-produced-on-the-surface-of-seamless-steel-pipe.html