FYN, June 14 (Xinhua)-- American letter announced that it signed a strategic framework cooperation agreement with Haitian Zhisheng Metal. The company plans to purchase several small and medium-sized models of Haitian metal cold chamber die casting and several large and super-large models in the next three years, and to carry out R & D technical cooperation in the field of large and super-large die casting. Haitian Metal will jointly develop a 20000 ton cold chamber die casting machine with the company.