Sequentially coupled thermal stress analysis in ABAQUS

I am modeling a composite slab subjected to standard fire (ISO 834-1). I have two models, a heat transfer model in ABAQUS / standard and a mechanical model in ABAQUS / Explicit due to the large deflections of my model.In my heat transfer model, I apply heat for 6000 seconds according to the experimt I' modeling.In my mechanical model I apply a pressure load in the first step. This load is kept constant in the second step and I import the nodal temperatures as a function of time as a predefined field through my heat transfer model. The problem is the computational costs in this second step that greatly increase my analysis time.I would like to know how can I accelerate the development of temperatures in my mechanical model? I've already tried the mass scaling technique but it makes me lose 
 precision in the results.How would you proceed in this situation?Thanks in advance.