Hardenability yog ib qho kev ntsuas ntawm cov hlau lub peev xwm los tsim martensite (harden) mus rau ib qho tob thaum quenched. AISI 4140 muaj qhov ua tau zoo heev vim nws cov ntsiab lus Cr thiab Mo. Qhov no yog quantitatively sawv cev los ntawm ib tug Jominy End-Quench test nkhaus, uas qhia tau hais tias yuav ua li cas hardness txo nrog nyob deb ntawm qhov kawg quenched.
Qhov tseem ceeb: Zoo hardenability txhais tau hais tias cov seem tuab (xws li qhov nruab nrab ntawm ib tug loj - txoj kab uas hla puag ncig bar) tseem yuav hloov mus rau ib tug tseem ceeb qhov tob ntawm martensite thaum lub sij hawm roj quenching, ua rau siab thiab uniform zog thoob plaws qhov chaw tom qab tempering. Rau 4140 puag ncig bar, siv tau los ntawm -hardening tuaj yeem ua tiav txog li 75-100mm (3-4 ntiv tes) inch nrog roj quench. Qhov no ua rau nws haum rau cov khoom loj, lub zog siab uas cov khoom tseem ceeb yog qhov tseem ceeb.