SU857293A1 - Steel - Google Patents

Description

(54) STEEL

The invention relates to metallurgy and may be applied in the production of steel and pipes thereof. Known for heat-resistant chromist steel l, containing, wt.%: 0.08-0.15 Carbon 0.1-0.5 Silicon 0.1-0.5 Manganese 4.5-6 Chromium 0.45-0.6 Molybdenum 0.4-0.7 Titanium 0.08-0.12 Cerium 0.01-0.,. 04 Calcium Rest Iron The closest to the technical essence and the achieved effect is steel 2, containing, wt.%: Carbon 0, 15 Manganese 0.5 Silicon "0.5 Chromium 4.5-6.0 Molybdenum 0.45-0.60 sulfur 0.025. PhosphoriO, 030 IronEsalting This is intended, main & thus, for the production of seamless pipes used at temperatures up to, elevated pressures and in aggressive environments. A disadvantage of the known steel is a large number of scrap and second-class pipes in the production of seamless pipes. The main, practically undamaged, defect in rolling tubes are the captives on their inner surface. Due to this defect, the waste of pipes in separate trunks reached 100%. Other defects are captives and hairs on the outer surface of the pipes, which can be eliminated by continuous cleaning of the outer surface of the billet or by selectively cleaning the pipes at the places of occurrence of defects. The purpose of the invention is to improve the technological plasticity of steels during hot mining and reduce, due to this scrap, seamless pipes over the captives on the inner surface. This goal is achieved by the fact that steel containing carbon, silicon, manganese, chromium, molybdenum and iron additionally contains aluminum and rare earth metals in the following ratio of components, wt.%: Carbon 0.06-0.15 Silicon. 0.10-0.50 Manganese0.10-0.50

4.5-6.00 0.45-0.60 0.005-0.015

flaxes

0,005-0,40 Else

Melting of steel is carried out in forty-ton electric steel-smelting furnaces, rolling of ingots on a pipe billet, (circle 150 mm) - at mills 1180 and 780

Ti subsequent rolling on tubes with a diameter of 150-130 mm - on mill 220.

The chemical composition and properties of the proposed steel are shown in the table.

From the materials presented in Table 5, it can be seen that alloying of steel with aluminum and rare-earth metals sharply reduces the loss of pipes through internal captives. The use of steel of the proposed composition allows to reduce the marriage of internal 0 captives to the level of 5-6%.

Claims (1)

Claim Steel containing carbon, silicon, manganese, chromium, molybdenum, iron characterized in that, in order to increase technological ductility during hot flashing of pipes, it additionally contains aluminum and rare-earth metals in the following ratio of components, wt.%: Carbon 0.06-0.15 Silicon 0.10-0.50 Manganese 0.10-0.50 Chromium 4,5-6,00 Molybdenum 0.45-0.60 Aluminum 0.005-0.015 Rare earth met alla 0.005-0.40 fifty Iron Rest