求翻译：试验结果表明，商用齿板铸件取样淬火不同温度回火试样的硬度有降低的趋势，200℃回火冲击值出现第一个峰值，超过200℃回火冲击值有下降的趋势，400℃回火出现马氏体回火脆性，超过400回火冲击值上升，出现回火脆性的主要原因与板条间奥氏体分解为断续的碳化物有关。是什么意思？

The results show that commercial tooth plate casting sample quenching temperature tempering sample hardness decreased to 200 ℃ tempering the impact of the first peak value of more than 200 ℃ tempering the impact of a downward trend, 400 ℃ tempering a martensitic temper brittleness, more than 400 tem

Test results show that business lug casting sampling different temperature hardened tempered with a sample of the hardness of the trend, reduce 200 °C tempered shock value with the first peak, more than 200 °C tempered shock value there is a downward trend, 400° C tempered martensite is brittle, and

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Test results indicates that, commercial tooth plate castings sampling quenching different temperature tempered specimen of hardness has reduced of trend, 200 ℃ tempered shock value appears first a peak, over 200 ℃ tempered shock value has declined of trend, 400 ℃ tempered appears horse's body temper

The test result indicated that, commercial toothed rack casting sample quenching different temperature tempering test specimen degree of hardness has the tendency which reduces, 200℃ the tempering impact value appears the first peak value, surpasses 200℃ the tempering impact value to have the drop t