Saturday, 3 August 2013

T26 - Iron and Steel Industry

China is one of the earliest countries in the world that invented and started iron working.  At the founding of the Peoples' Republic of China, the Iron and Steel Industry was still very much under-developed.

With assistance from Soviet Union, Anshan Iron and Steel (鞍钢), Wuhan Iron & Steel (武钢), Baotou Iron and Steel (包钢), etc, were built and after that the Iron and Steel Industry in China grown by leaps and bounds.  The annual steel production volumes increased from 18th in the world in 1952 to 9th in the world in 1957.

In the 1960's and 70's, the standard of China's Iron and Steel Industry continued improving, with many new products developed for the modernization of agricultural, industrial, national defence and scientific fields. 

To reflect the importance of iron and steel industry to the whole national economy of China, a set of five stamps depicting the five essential stages of iron and steel industry production process was issued on July 22, 1978.

(5-1) 8 fen, Coking  炼焦
(5-2) 8 fen, Iron making  炼铁
(5-3) 8 fen, Steel making  炼钢
(5-4) 8 fen, Steel rolling  轧钢
(5-5) 8 fen, Finished products  成品

(5-1)【Coking】The coking process consists of heating coking coal to around 1000-1100ºC in the absence of oxygen to drive off the volatile compounds (pyrolysis).  This process results in a hard porous material - coke.  Coke is produced in a coke battery which is composed of many coke ovens stacked in rows into which coal is loaded.  The coking process takes place over long periods of time between 12-36 hours in the coke ovens.  Once pushed out of the vessel the hot coke is then quenched with either water or air to cool it before storage or is transferred directly to the blast furnace for use in iron making.  The stamp depicted the coking operating scene in Capital Iron and Steel Company (首都钢铁厂).

(5-2)【Iron making】Iron ore is mined in around 50 countries – the largest producers are Australia, Brazil and China. Around 98% of iron ore is used in steel-making.  During the iron-making process, a blast furnace is fed with the iron ore, coke and small quantities of fluxes (minerals, such as limestone, which are used to collect impurities).  Air which is heated to about 1200°C is blown into the furnace through nozzles in the lower section.  The air causes the coke to burn, producing carbon monoxide which reacts with the iron ore, as well as heat to melt the iron.  Finally, the tap hole at the bottom of the furnace is opened and molten iron and slag (impurities) are drained off.  The stamp depicted the iron making scene in Maanshan Iron and Steel Company (马鞍山钢铁厂).

(5-3)【Steel making】The most commonly applied process for steel-making is the integrated steel-making process via the Blast Furnace – Basic Oxygen Furnace.  In the basic oxygen furnace, the iron is combined with varying amounts of steel scrap (less than 30%) and small amounts of flux.  A lance is introduced in the vessel and blows 99% pure oxygen causing a temperature rise to 1700°C.  The scrap melts, impurities are oxidised, and the carbon content is reduced by 90%, resulting in liquid steel.  The stamp depicted the Oxygen Furnace in Shanghai Iron and Steel Company (上海钢铁厂).

(5-4)【Steel rolling】In steel making, rolling is a metal forming process in which steel stock is passed through a pair of rolls.  Rolling is classified according to the temperature of the steel rolled.  If the temperature of the steel is above its recrystallization temperature, then the process is termed as hot rolling.  If the temperature of the steel is below its recrystallization temperature, the process is termed as cold rolling.  The stamp depicted the steel rolling scene in Wuhan Iron & Steel Company (武汉钢铁厂).

(5-5)【Finished products】After steels are made into final products, they are shipped, mainly by trains, to other factories or places where there are demand for steel.  The stamp depicted the busy finished products shipping scene at Shanghai Iron and Steel Company (上海钢铁厂).

T26 – Iron and Steel Industry  钢铁工业
Issue Date: 1978.7.22
Serial Number:T26
Scott Number:1415-1419
Michel Number:1425-1429
Number of stamps in Set:5
Denomination:8 fen for stamp 1, 2, 3, 4, 5
Quantity of Issue:14,000,000 for stamp 1, 2, 3, 4, 5
Sheet Composition:35 (5 X 7) for stamp 1, 2, 3, 4, 5
Size of stamps:62 X 26 mm for stamp 1, 2, 3, 4, 5
Designer:Sun Chuanzhe 孙传哲
Printing Process:Photogravure
Printing House:Beijing Postage Stamp Printing Works

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