Baosteel Group, China's largest steelmaker, has begun construction of its 50-50 steelmaking joint venture with Hansteel Group, with a total investment of $2.6 billion, said industry sources. The venture, Hanbao Steel, will have an annual steel plate capacity of 4.6 million tons. The National Development and Reform Commission first approved the venture in northern China's Hebei Province in December 2005. The plant is expected to become operational at the end of 2010.