1974. 04.20 : Established Sam-Jung Steel Industry -PC bridge cone, sheath duct, spiral, steel wire etc.

1986. 01. 01 : Converted to Sam-Jung Steel Corporation -PC cone, wedge, sheath duct, spiral, bearing shoe

1990. 02. 02 : Review of Wedge specification -Reliability and endurance test

1990. 05. 01 : Changed a firm name to 'Sam-Jung strand cone' -Moved to a newly constructed building in Namdong Industrial District

1990. 06. 01 : Safety and wedging effect study completed -Report on strand cone wedge characteristics published

1990. 08. 22 : Acquired a patent of invention of solid lubricant manufacturing method

1991. 02.15 : Presented result of research on 'PC strand cone wedge' fatigue test through the steady tensioning and repeated weight loading

1992. 07.16 : Report on Sam Jung strand cone wedge and strand weight loading and strand destructibility test

1993. 04. 20 : Test of the wedge destructibility under maximum weight loading and slip completed

1994. 12. 21 : Acquired ISO 9002

1995. 03. 07 : Registered as a trade business firm

1996.11. 29 : Designated as a company under Article 74 of Military Law

1997. 06. 26 : Approved new PSC tension technology (Registration #66)

1997. 08. 01 : Approved as a superior partner by 'Hyundai Construction Co., Ltd.'

1998. 02. 21 : ISO 9002

1998. 02. 20 : Designated as a '98 strategical item machine component core parts developer - White Metal Bearing

1998. 04. 02 : Technology prize awarded (PSC tension technology)

1999. 12. 20 : Technology consulting Contract with 'Bridge engineering research center, Sung-Kyun-Kwan University'.

2000. 04. 25 : Changed a firm name 'Sam-Jung P.S Systems Co., Ltd' & Changed a president