After quenching the blade is there anything else needed to be done before I start sanding ?
YES! "Heat Treating" is generally divided into two (or more depending on steel type) steps. "Quenching" also known as "Hardening" and Tempering.
In short, the goal of Quenching/Hardening, is to make the steel as physically hard as it can be. The problem is that along with hardness, comes brittleness. The second step with most forgable steels is Tempering.
Tempering is best described as a Controlled Softening. This is accomplished by heating the blade to a much lower temp, for a given duration, than used in the hardening step. The goal being to leave enough hardness in the blade for it to hold an edge, but take enough hardness away to ensure it's not brittle.
For most forgable steels, they can be tempered in a typical kitchen oven. The temps range from 350F to 500F+ depending on the steel and the desired end hardness. Likely the most important thing is to ensure the oven is accurate. Changes take place in the steel every 25 degrees F. So if the oven/oven dial isn't accurate, you can chase your tail for a LONG time.
There are a lot of other things occurring in the steel during tempering, and I suggest educating yourself on various tempering methods for different steels...... each steel can be tempered at different temps depending on geometry, edge thickness, etc. Most of us have sacrificed a lot of otherwise good blades learning what temps and times work best for the type of steel(s) we use, and the geometry we put on it.
When it comes to "sanding", the job is MUCH easier on a tempered blade versus one that you attempt to "sand" fully hardened.