First of all, what is your CPU cooler? You will need a pretty decent air cooler (or closed loop liquid cooler) to run at 4.6GHz. Don't expect to do that on the stock Intel cooler. With that said, overclocking is mostly trial and error. Every chip is different, and some people get better chips than others (known as "winning the silicon lottery"). What this means is that they get a higher overclock with less voltage required than others. The reasons for these differences are complex, but in a nut shell, some days there is better silicon manufactured than other days.
I find that the best overclocking results start with knowing my stock speed voltage and temp use in a stress test program. That gives you a baseline to work with. You need to understand your CPU's "personality." From there, I will slowly crank up the multiplier and voltage (Vcore), watching temps in each step of testing. (D0 NOT allow the motherboard BIOS to adjust your voltage with Vcore set to "AUTO"...set that to manual and adjust in steps as mentioned. AUTO generally uses more voltage than is really necessary for a given clock speed).
The average voltage required at 4.6GHz should be around 1.35v, plus or minus a variation of .03v or so depending on how good your chip is. If you find you need upwards of 1.4v to run at 4.6GHz, then you didn't get a very good overclocking chip and need to dial it down to 4.5GHz or even 4.4GHz. The max long term voltage recommended to not exceed on a Skylake is 1.35v, although some are okay with up to 1.40v as 7x24 use (I would not recommend that). Intel says the max "safe" voltage is up to 1.45v. But on a 14nm chip, I wouldn't even come close to wanting to testing that without a serious liquid cooling system, as heat becomes exponentially a larger problem on thinner silicon and more voltage.
Finally as another thought, I have two different BIOS settings saved in my 4690K build. One setting is for overclocked, and the other is for standard/stock use. At startup I just go into BIOS and click when preset I want to boot with. Excellent tool that ASUS has, and I'm sure other board makers have something similar. When you manually set a voltage setting in BIOS, that is what it runs at all the time compared to running the CPU at stock and then letting it throttle down automatically when not under load. So there's another useful tip in extending the life of an overclocked CPU: don't always run it overclocked if you don't have to! Here's a good short review on overclocking the 6700K and results. Good luck!
http://www.anandtech.com/show/9533/intel-i7-6700k-overclocking-4-8-ghz