Turning Hardened Steel and CBN inserts 

Introduction

We usually meet the following problems when hard turning quenched steel work piece,especially when rough machining quenched steel,interrupted turning,grooving machining,and the roughness of quenched steel after turning.Most people can’t choose the suitable cutting tools for turning quenched steel,kinds of machining problem appeared,such as:roughing,interrupted machining.Now we mainly discuss the common problems and introduce CBN insert.

The problems when hard turning quenched steel

1.Rough machining quenched steel

Turning Gears after heat-treatment,the hardness of gear and gear ring after quenching or cemented quenching was usually above HRC55,some even reach HRC60~HRC65.Common Gear materials are: 20Cr,20CrMnTi,40Cr,42CrMo,35CrMo. Some gear distorted serious,especially the big gear ring,big gear after cemented quenching,like high-speed rail gear, engineered machinery big gear ring,heavy industry big gear ring,etc,those big gears gear rings deformation was very big,this case involved rough machining quenched steel.At the same way,rough machining tool steel usually happened in manufacturing of die steel.

2.The interrupted machining of the quenched steel

Interrupted turning is a challenge,even for quenched steel hardness reach about HRC60.Especially when high speed turning quenched steel,if the work piece has interrupted turning,the cutting tools will stand more than 100 times impact per minute,it's a big challenge for the cutting tools.For example,Turning hardened gear instead of grinding,and the Vehicle gear occupy 62% in the whole gear industry,and auto gear occupy 62% in the Vehicle gear.It is said that the auto gear occupy about 40% in the whole gear market.Although turning quenched steel instead of grinding was wide spread,there are still some problem during machining the auto quenched gear,such as,there some oil hole in the auto gear,this will happen the interrupted turning trouble,many CBN inserts easily happen to chipping when machining the oil hole,its hard to guarantee the gears position tolerance.

3.Grooving machining quenched steel

Such as:hard turning the synchronizer sliding sleeve gate after quenched,the CBN inserts lifetime still not so satisfied though CBN inserts manufacturer research specialized CBN inserts used for synchronizer sliding sleeve.

4.The roughness of hard turning quenched steel

The bearing steel after quenching usually require a much good finish by turning,Gcr15 steel is a common bearing steel,the hardness after quenching is about HRC62,as the precision and finish of the bearing have a high requirement.Even if adjust the CBN insert edge well,it is still impossible to get a Ra 0.4 finish of the quenched steel after turning.

Choosing Cutting tools when machining the quenched steel

There are few aspect to choose CBN cutting tools for hard turning quenched steel in turning field:one is the choice of cutting tools material ,usually when cutting the quenched steel work piece which hardness less than HRC50 and with a small feed rate,a small cutting depth,ceramic cutting tools will be a better choice.CBN insert suit for the work piece which hardness is harder than HRC50,meanwhile ceramic insert need avoid semi-finishing and roughing,but CBN inserts can suit for interrupted turning,heavy rough machining.Another is the choice of CBN inserts manufacturer/grade and edges processing,a good CBN insert not only won’t chipping during rough machining process,but also can keep a longer working life and get a good surface finish when finishing efficiently.

When finish turning quenched steel,we can choose welding CBN insert.When rough machining or interrupted turning,we need choose the solid/overall CBN inserts,there just a few manufacturer produce this type CBN inserts,Halnn did best in China,BN-S10 CBN inserts from Halnn superhard material make it successful to rough machining and interrupted turning quenched steel industry,and Halnn superhard material company enjoy a highl reputation in world cutting tools industry.

More about our products,please click http://www.halnntools.com/pro/,or contact with us :halnntools@gmail.com,whatsapp:+8615036165377,skype:cbn_inserts_angels