The reasonable parameters of CBN inserts Hard turning bearing steel after quenching

1.The hardness standard conversion of the bearing steel after quenching

The hardness of bearing steel after quenching usually is above HRC45,some even more than HRC60,the conversion between Rockwell hardness and Vickers hardness,we can get a very accurate result with additional formula HRC=100-37353/(HV+200),this formula is so convenient in the practical application.Common hardness comparison table which people usually used is not suit for quenched steel.

2.When need CBN inserts hard turning bearing steel after quenching

Firstly,choosing the appropriate insert material,if the hardness of the bearing steel after quenching is above HRC55,choose CBN insert is the best choice,if the hardness is below HRC45 and finishing process,you can choose one better after comparing the economy between CBN insert and ceramic insert aim at this case.If just hard turning quenched steel infrequent,you can think about YT726 or others carbide turning tools.

Notice: PCBN inserts(Halnn company BN-H10,BN-H20 grade)cutting depth usually is within 0.3mm,and need try to avoid interrupted turning,can get a good surface roughness when finish turning bearing steel,realize turning instead of grinding.If the cutting depth is above 0.3mm or interrupted turning quenched steel,BN-S20 grade from Halnn superhard material company can meet this requirement completely.(BN-S20 grade CBN inserts cutting depth can reach above 7mm when hard turning quenched steel) 

3.The cutting parameter of CBN inserts hard turning bearing steel after quenching 

CBN inserts hard turning quenched bearing steel: cutting speed usually is 80-120m/min,if the work piece has a much higher hardness,its better choose a lower cutting speed,for example,its better to turning the work piece with 70HRC hardness by 60-80m/min cutting speed,if the lathe machine has a high rigidity, Halnn BN-S20 grade CBN insert almost can finish the most allowance just with one feed,just leave about 0.3 as the finishing allowance,the feed rate was choose according to the roughness require,suit about 0.1mm/r.

4.CBN inserts parameter Selection 

CBN inserts parameters:usually chose 0.2*20 degree chamfer when roughing or interrupted machining,choose 0.1mm width chamfer when finishing,the tools nose radius of circular arc according to the detail condition.

5.Notes when using CBN insert machining quenched bearing steel

(1)dry cutting,if there are some reason so that need add water,you can use Halnn company BN-H10 grade CBN inserts,this grade insert has a good lifetime under wet cutting.

(2)Choose the CBN inserts grade:Need chose BN-H20 when turning the bearing steel instead of grinding,try to shorten the extended length of holder for decrease the vibration and get a better surface roughness.If the machining allowance of the quenched bearing steel is a little big,we recommend BN-S20 grade CBN insert.(This two grade CBN insert are both researched by Halnn superhard material Co.,Ltd.,win national key technology of production, study and research project results,has the best toughness and lifetime in the superhard cutting tools industry)

More details,http://www.halnntools.com/pro ,Or contact with us halnntools@gmail.com,whatsapp:+8615036165377,skype:cbn_inserts_angels