* Nikkei up 0.9 pct, but investors still cautious * Steelmakers gain after U.S. peer AK Steel increases prices * Hoya, Tokai Carbon fall on quarterly earnings * Futures trading glitch stems volume slightly * China "unlikely" to ease before leadership change -analyst By Sophie Knight TOKYO, Aug 7 (Reuters) - The Nikkei share average rose on Tuesday, extending the previous session's sharp rally and in step with global markets' overnight gains as investors continued to adjust positions in the last throes of Japan's earnings season. Steelmakers provided ballast for the market after U.S. peer AK Steel announced price increases, signalling business had improved and helping JFE Holdings, N ippon Steel Corp an d Sumitomo Metal Industries Ltd rise between 4.9 and 5.4 percent.