No it isn't. Social services have a lot of experience in working to support those experiencing domestic violence, and their chlidren. They will only take children into care if they believe that this is the only way to keep them safe.
How Social Services can help
A social worker could talk to you about the best ways you could improve your safety and that of your children.
Social workers can provide information and referrals to other support services for those experiencing domestic violence (refuges, legal advisors, counsellors, etc.)
If your partner is also hitting or hurting the children then social services would try to work with you to find a way to prevent this from happening again. This may involve finding alternative safe accommodation for you and your children or getting your partner to leave and stay away from the family home (see Practical Help: Your legal rights for further information on injunctions).
Social services can also help in other ways such as helping you in getting childcare (e.g. childminders or nursery places) for your children.
For more information on how social services can help see Sources of Support.