鋼材的化學成分是影響淬透性最重要的因素之一。凡是在三角異型鋼管鋼材中引起“c”曲線右移或左移的合金元素，都對淬適性有著極大的影響。使“c”曲線右移的元素將提高鋼的淬透性;使“c”曲線左移的元素將降低鋼的淬透性。如45鋼與40Cr鋼，其含碳量差不多，但，由于前者不含鉻元素，后者含鉻元素約1%，在同等的熱處理條件下，它們的淬透性就顯然不同，45鋼只能淬遠3.5-9.5毫米，而40Cr鋼可淬透25-32毫米。

The chemical composition of steel is one of the most important factors affecting hardenability. The alloying elements which cause the "c" curve to move right or left in the triangular shaped steel pipe have a great influence on the quenching suitability. The hardenability of steel will be improved by the elements shifting the "c" curve to the right, while the elements shifting the "c" curve to the left will reduce the hardenability of steel. For example, 45 steel and 40Cr steel have similar carbon content, but because the former does not contain chromium element and the latter contains about 1% chromium element, their hardenability is obviously different under the same heat treatment conditions. 45 steel can harden only 3.5-9.5 mm, while 40Cr steel can harden 25-32 mm. 三角異型鋼管形狀尺寸、加熱溫度、冷卻方式等，在不同程度上都影響著鋼的淬透性。形狀尺寸小、加熱溫度高，連續(xù)冷卻等都能在一定程度上提高淬透性;而形狀尺寸大、加熱溫度低、等溫冷卻等卻能使淬透性下降。

The shape, size, heating temperature and cooling mode of triangular shaped steel pipe affect the hardenability of steel to varying degrees. Small size, high heating temperature and continuous cooling can improve the hardenability to a certain extent, while large size, low heating temperature and isothermal cooling can reduce the hardenability.