| March |
1955 |
Kenji Kakihara, the current chairman,
established Jonan Steel Shokai in Omori-kita, Ota-ku, Tokyo,
to sell steel materials as a private management company. |
| December |
1967 |
Jonan Steel Mill Corporation purchased land at 5-13-35
Ryoke, Kawaguchi city, and started to construct a new rolling
plant as a first phase of new mill constraction. |
| November |
1969 |
The company built a steel making plant as
second phase of the construction. This plant started
production with a 20-ton electric furnace. The continuous
production system from the steel-making process to the rolling
process was started. Capital was increased to ￥48 million with
investment by Tokyo Small and Medium Business Investment &
Consultation Co., Ltd. |
| November |
1971 |
Authorized to place Japan Industrial Standard (JIS)
indication on reinforcing bar steel. |
| June |
1972 |
Continuous casting machine was
installed. |
| August |
1973 |
The 20-ton electric furnace in the steel-making plant was
replaced by a 40-ton electric furnace, Rationalization of the
rolling line was done. Which cabled 15,000 tons of production
monthly. |
| December |
1982 |
The steel making mill and the rolling mill
achieved monthly production of 25,000 tons each. |
| November |
1988 |
Rolling line and accuracy adjustment line were replaced by
new lines. Both the steel-making mill and the rolling mill
established 40,000-ton production systems. |
| September |
1989 |
The continuous casting machine in the
steel-making plant was replaced by a new machine. |
| January |
1994 |
The finishing rolling machine in the rolling plant was
replaced by a block mill. |
| January |
1997 |
The oxygen generator was replaced by a new
one. The intermediate mill in the rolling plant was replaced
by a block mill. |
| December |
1999 |
The plants achieved conformity with ISO 9001:1994 quality
system examination, and were certified and registered. |
| March |
2001 |
The Purchasing Department purchased a iron
scrap radioactive ray detection monitor. |
| December |
2004 |
The motors of the building dust collectors were changed to
inverter-controlled motors to achieve energy saving. |
| May |
2005 |
The motors of the direct-suction dust
collectors were changed to inverter-controlled motors to
achieve energy saving. |
| April |
2009 |
Authorized to place Korean Industrial Standards (KS)
indication on reinforcing bar steel. （KS D 3504） |
| December |
2009 |
The plants achieved conformity with ISO
9001:2008 quality system examination, and were certified and
registered. |
